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Posted: 5/3/2009 11:06:31 PM EDT
[Last Edit: Zhukov]
Link Posted: 5/3/2009 11:16:46 PM EDT
[Last Edit: Tim_W] [#1]
#1 the 6.8 upper comparison chart
chart
Just the facts-subject to edits as info compiled-
latest handload  velocities- apx 58000psi in the Xtreme, 12 twist 3 groove and 11.25 twist polygonal barrels only.
Do not try these in 10 twist barrels or barrels with SAAMI chambers.
EXPERIENCED LOADERS ONLY   ALWAYS START A FEW GRAINS LOWER AND WORK UP.

April - 2009
90gr TNT-2.30" 29-29.5gr RE7 very accurate-2950fps 16" Xtreme barrel
90gr TNT- 2.3" 30.5 gr Max RE7 -3056fps 16" Xtreme barrel

80gr GS HV- 2.3" 30.6gr max RE7-3228fps 16" Xtreme barrel

85gr Barnes TSX-2.3" 30.6gr max RE7-3209 fps 16" Xtreme barrel

105gr GS SP-2.51" 30.5gr max RE10X-2950fps 16" Xtreme barrel


all 110s
110gr Nosler-2.3" 30.2gr max RE10X-2870fps 16" Xtreme barrel
110gr pro-hunter
110gr Vmax
110gr TSX

Energy and exterior ballistics info coming

The 6.8 performance report, Aug. 2008 - compares chambers, twist and rifling designs  by using pressure and velocity.
report


As Cold says below, If you buy it off the rack and shoot factory ammo , availability of both will be very important.
LMT, LWRC, DPMS, CMT, Armalite, I.T.S. all make 6.8 bolts
PRI, CP and Barrett make 6.8 mags
almost every major manufacturer makes the 6.8 and many custom shops do also.
Link Posted: 5/4/2009 12:10:26 AM EDT
[Last Edit: Cold] [#2]
Link Posted: 5/4/2009 12:56:46 AM EDT
[#3]
Personally, I looked at both cartridges very closely before i chose and I went with the 6.8SPC.
1) The AR-15 is not a precision shooting platform. I would take a bolt action for distance so I don't really care what the cartridge does at a thousand yards.
2) I wanted an upper for CQB type situations. Ballistics wise, the 6.8 SPC does a better job out of a short barrel.
3) Terminal performance out of a 6.8 in the 0-300 yard range is better. I can get effective terminal performance in this range out of a 12.5" 6.8 SPC barrel.
4) Generally speaking, ammo is cheaper for the 6.8 SPC.
5) The 6.8 SPC is still evolving and has steadily improved due to more people pushing its limits. By comparison, the 6.5 Grendel seems much more static.
6) There is a lot more manufacturer support for the 6.8 SPC than for the 6.5 Grendel.

I think both cartridges have a lot in common but in the end, for my purposes, the 6.8 SPC won.
Link Posted: 5/4/2009 3:27:42 AM EDT
[#4]
Originally Posted By GPalmer:
Personally, I looked at both cartridges very closely before i chose and I went with the 6.8SPC.
1) The AR-15 is not a precision shooting platform. I would take a bolt action for distance so I don't really care what the cartridge does at a thousand yards.
2) I wanted an upper for CQB type situations. Ballistics wise, the 6.8 SPC does a better job out of a short barrel.
3) Terminal performance out of a 6.8 in the 0-300 yard range is better. I can get effective terminal performance in this range out of a 12.5" 6.8 SPC barrel.
4) Generally speaking, ammo is cheaper for the 6.8 SPC.
5) The 6.8 SPC is still evolving and has steadily improved due to more people pushing its limits. By comparison, the 6.5 Grendel seems much more static.
6) There is a lot more manufacturer support for the 6.8 SPC than for the 6.5 Grendel.

I think both cartridges have a lot in common but in the end, for my purposes, the 6.8 SPC won.



A good summation, generally speaking, above.

-However, I would add that my 12 twist, 3 groove ARPerformance, DMR chambered barrel is a precision weapon, capable of one-hole groups with Speer 90 grain TNT accuracy loads using RE7, and recently with 85 grain TSX's loaded with RE7.  The 6.8 is an inherently accurate cartridge. despite all the flogging it takes over BC, sectional density and extreme range performance.  I do not believe that the hundreds of animals I have killed with 6,.8 SPC know anything about these variables....or so it would seem from their rapid demise at its behest.

-The 12.5" barrel will deliver the 85 grain TSX at 2975 FPS, and is effective to 300 yards.  Another excellent point, considering that the Grendel requires a much longer barrel to generate a similar velocity.  Cartridge / case efficiency of the 6.8 is near the highest of any I have ever loaded.

-The 6.8, given the industry support, and shooter stimulated evolution, is now a different cartridge versus that which was released 4 years ago.  Velocities are higher, bullets are much more up to date and the barrel specs have also evolved to allow for much better performance.  The Grendel has not advanced in its performance much (though it is not "bad" performance), so the comparison now has shifted toward to 6.8, especially when you consider the performance achieved by 6.8 with short barrels, IMHO.

- suppliers of 6.8 guns, and gear >>>>>>>>> 6.5 Grendel.....it is that simple.

- ammo prices are high for both, and while Wolf makes Grendel, that currently beats any 6.8 price out there.  Personally, I wouldn't shoot Wolf, in a $1600 gun, but once SSA releases their plinking ammo that gap will narrow substantially.  SSA's plinking ammo will be high quality stuff, bet on that.  If you reload, then you are GTG.

- Prices for 6.8 guns are generally quite a bit more affordable when you factor in the entry level Stag guns, which are good quality and have been upgraded to the 11 twist and SPC II chamber.
Link Posted: 5/4/2009 4:47:45 AM EDT
[Last Edit: Zhukov] [#5]
<Off topic comments removed - Z>




When I was making this decision the 6.8 was at that moment in it's history when it was a big disappointment. Real life performance was not even close to advertised performance. I saw no benefit over my 5.56 rifles with 77 grn bullets. Now the 6.8 is really starting to cook (kudos to those that are pushing it), but still it wouldn't do what I wanted it to do. I was building a rifle for one purpose, fast moving sniper style matches. I considered an AR10, and actually ran one in Zak Smith's PRTC match where it was nothing but trouble, I spent more time fixing it than shooting it.





The Grendel could do what I wanted. Hit steel out to 1000 yards with low recoil and  fast follow up shots.





Personally I don't really understand all the fighting, they were designed for completely different things but there is some overlap in their capabilities. The 6.8 was designed to be a replacement for 5.56 in military small arms. The Grendel was designed first for punching paper at long range, and then as something that could be used on deer sized game from an AR15 with better performance than 223. There is some overlap in performance in that out to 500 yards both 6.8 and 6.5 Grendel are improvements over 5.56 with the new and improved 6.8 slightly outperforming the Grendel at those distances and and the Grendel outperforming the 6.8 beyond that.





Both benefit greatly from reloading, especially if you don't want your ammo supply dependent on small runs of a Wildcat cartridge (Yes, I know that technically since there are SAAMI specs for the 6.8 it's not really a wildcat, but I don't believe there are SAAMI specs for 6.8 SPC II, tell me if I'm wrong on this). Both ammo supplies run fat then thin then fat again.





Right now I feel covered between 5.56 and Grendel I can cover anything I might want to shoot up to Elk (though I will still use my 270 WSM or my 450b this Elk season) and out to 1000 yards on steel or paper. If I had 5.56 and 6.8 and then decided I wanted to shoot sniper matches out to 1000 yards, I would feel a need to buy another rifle for that purpose.





I'm happy with my choice, I make my own ammo and have never run out. It takes me about 32 MOA of adjustment to hit steel at 1000 yards, and I know for a fact that at 700 yards I can open and close the door on a MGM Precision target with the 308 door on it, I did it at a local sniper match. Something a 223 can't do cuz it doesn't have the power left at that range.
So it's not just about availability, there are differences between the two calibers. If availability is a persons only concern, then I suggest that they stick with a rifle in 5.56.
 
Link Posted: 5/4/2009 4:55:22 AM EDT
[#6]
Originally Posted By GPalmer:

1) The AR-15 is not a precision shooting platform. I would take a bolt action for distance so I don't really care what the cartridge does at a thousand yards.



I'm not sure where you get that from, I personally have Two 5.56/223 AR and two Grendel AR's that are all sub-moa rifles. All built by me, no specialized processes or treatments, just quality parts.

Hell, even my 450b shoots 1.5 moa groups.
Link Posted: 5/4/2009 8:03:26 AM EDT
[#7]
Originally Posted By MudBug:
Originally Posted By GPalmer:

1) The AR-15 is not a precision shooting platform. I would take a bolt action for distance so I don't really care what the cartridge does at a thousand yards.



I'm not sure where you get that from, I personally have Two 5.56/223 AR and two Grendel AR's that are all sub-moa rifles. All built by me, no specialized processes or treatments, just quality parts.

Hell, even my 450b shoots 1.5 moa groups.

A precision rifle carries a guaranteed 1/2 MOA or better performance. There a a LOT of bolt actions I can buy that meet those specs. Sub MOA doesn't mean precision and neither does 1.5 MOA. I think your definition of precision has shifted to match your platform.
Link Posted: 5/4/2009 8:07:00 AM EDT
[Last Edit: Zhukov] [#8]
<Off topic comment removed - Z>

Link Posted: 5/4/2009 9:07:37 AM EDT
[Last Edit: Zhukov] [#9]
<Off topic comments removed - Z>


Link Posted: 5/4/2009 9:27:30 AM EDT
[Last Edit: Zhukov] [#10]

<Off topic comment removed - Z>





I'd really rather keep this thread on topic as requested by Zhukov. That topic is "6.8 SPC versus 6.5 Grendel." I would still buy a bolt action if I were serious about shooting 1000 yards. That weighed in my decision between the cartridges in this platform, further discussion about bolt action versus AR-15 as a precision platform strikes me as off topic. If you bought the 6.5 Grendel because you feel the AR-15 is a great precision platform and that cartridge allowed you to experience it fully, please feel free to share your experience!
 
Link Posted: 5/4/2009 9:57:03 AM EDT
[#11]
The 6.8 SPC is the clear winner. It has more supplys available and more manufacturers to choose from.
If you reload, the long distance advantage that the 6.5 has over the 6.8 can be nullified. The 6.8 spc is gaining customers
at a much faster rate than the 6.5 grendel is and that means more and more parts will become available.
Link Posted: 5/4/2009 10:27:01 AM EDT
[Last Edit: Cold] [#12]
Link Posted: 5/4/2009 11:04:59 AM EDT
[Last Edit: Zhukov] [#13]
Link Posted: 5/4/2009 11:14:30 AM EDT
[#14]
I have reloading manuals with published data for 6.8 SPC and nothing for 6.5 Grendel.  The 6.8 Remington SPC is commercially avaliable through more manufacturers of rifles and ammunition while the 6.5 Grendel™ is in fact a proprietary cartridge trademarked and owned by Bill Alexander and thus doesn't have the avaliability in rifles or ammunition the 6.8 has.

That is the logistical argument.

The ballistic argument is moot––-they are both intermediate range cartridges as intended and any arguments about their effective range is nothing more than a pissing contest.
Link Posted: 5/4/2009 11:58:31 AM EDT
[#15]
Since 95% of the AR-owner universe will never shoot out past 500 yards (and 99%+ will never shoot out to a thousand), talking about the performance difference between 6.5G and 6.8SPC is kind of moot: they both overlap quite a bit, as has been pointed out, and they both outperform even the best 5.56 loads by a wide margin.

Therefore, I have to agree with Cold's statement that it comes down to what you can build, buy, and shoot. Unless Bill Alexander is planning to announce a tectonic shift in 6.5G production capabilities, 6.8SPC components, ammo, and factory guns are much more readily available.

On a more personal note, my experience with 6.5G left me with the impression that the round is finicky. You need to bed the gas block and barrel extension using Loctite, you need to match barrel twist to barrel length and projecticle weight, you have to be careful how you break in the barrels, you need to let the VLD projectiles go to sleep, etc. Frankly, I've never had to do any of this stuff to shoot 6.8SPC accurately. Of course, others may have a much different 6.5 story to tell.
Link Posted: 5/4/2009 1:11:17 PM EDT
[#16]
Link Posted: 5/4/2009 1:35:32 PM EDT
[#17]
I went through this a couple years ago and picked the 6.8.  Not because I thought it was miles better than the 6.5, just more available.  Besides, I reload for my .270 and already have a three way trimmer head for that cartridge.  I'm not going to be using a belt-fed anything so that doesn't come into play.  Also, the last time I shot a 1000 yards was at a life size steel cutout of a buffalo with a 45-70.  And yeah, you can lob bullets consistantly into that target at that range with a huge lead bullet.  I wish I had a place I could shoot 1000 yards on a regular basis, but I don't.  If I did, I'd probably opt for a tricked out bolt gun in 338 Lapua or 416 Barrett.

Back on topic, either will do.  Hell, maybe someday I'll get a 6.5
Link Posted: 5/4/2009 2:05:03 PM EDT
[Last Edit: MudBug] [#18]
Originally Posted By vmpglenn:
On a more personal note, my experience with 6.5G left me with the impression that the round is finicky. You need to bed the gas block and barrel extension using Loctite, you need to match barrel twist to barrel length and projecticle weight, you have to be careful how you break in the barrels, you need to let the VLD projectiles go to sleep, etc. Frankly, I've never had to do any of this stuff to shoot 6.8SPC accurately. Of course, others may have a much different 6.5 story to tell.



Not true, not true at all.

Neither of my Grendels have any of that done to it and both are fine shooters.

Bill A does all that bedding stuff because he believes it's important. It's not a uncommon practice with AR's built for accuracy, It's been done for years by the high power/DCM crowd, benchrest shooters, and prairie dog smackers because they feel it leads to more consistency in the platform, it has nothing to do with caliber. If one of those guys was building a highpower rifle in 6.8 they would bed the barrel and gas block. I do not do it and both my Grendels are good performers.

And really, how can you say barrel break-in is caliber specific? personally I think it's not needed in any caliber, but those that do believe in it do it regardless of caliber, those same people bedding their 6.8 for highpower just might follow standard break-in also because they feel it's important.

You also need to match barrel twist and bullet weight in any rifle you shoot.

Sorry if this seems off topic, but I won't let BS like this stand without being disputed in a thread is supposed to be the be all, end all on this topic.

Link Posted: 5/4/2009 4:06:52 PM EDT
[Last Edit: vmpglenn] [#19]
Originally Posted By MudBug:
Originally Posted By vmpglenn:
On a more personal note, my experience with 6.5G left me with the impression that the round is finicky. You need to bed the gas block and barrel extension using Loctite, you need to match barrel twist to barrel length and projecticle weight, you have to be careful how you break in the barrels, you need to let the VLD projectiles go to sleep, etc. Frankly, I've never had to do any of this stuff to shoot 6.8SPC accurately. Of course, others may have a much different 6.5 story to tell.



Not true, not true at all.

Neither of my Grendels have any of that done to it and both are fine shooters.

Bill A does all that bedding stuff because he believes it's important. It's not a uncommon practice with AR's built for accuracy, It's been done for years by the high power/DCM crowd, benchrest shooters, and prairie dog smackers because they feel it leads to more consistency in the platform, it has nothing to do with caliber. If one of those guys was building a highpower rifle in 6.8 they would bed the barrel and gas block. I do not do it and both my Grendels are good performers.

And really, how can you say barrel break-in is caliber specific? personally I think it's not needed in any caliber, but those that do believe in it do it regardless of caliber, those same people bedding their 6.8 for highpower just might follow standard break-in also because they feel it's important.

You also need to match barrel twist and bullet weight in any rifle you shoot.

Sorry if this seems off topic, but I won't let BS like this stand without being disputed in a thread is supposed to be the be all, end all on this topic.



That's great that your experience with 6.5G has been much more positive. That's two data points on opposite ends of the spectrum...

Here's an interesting article where Bill Alexander talks about barrel twist in 6.5G (has to do with the extreme variation in ogives on the 6.5 bullets used in Grendel loads), as well as the gas block/extension bedding. There have been threads at 65grendel.com where Bill also talks about these issues. He's even gone so far as to say that certain lengths of barrel should have certain twists to maximize accuracy. There doesn't seem to be a need to do this on 6.8 barrels. I can shoot anything from 85gr to 130gr through my 1:11 twist 6.8SPC barrel with excellent results –– and that's through either my 18" WOA or my 12.5" Cardinal Armory.

Here's a thread on 65grendel.com where Bill talks about using JB paste on Satern match barrels during break-in. He specifically mentions that Grendel has a few peculiarities.

Again, compared to 6.8SPC - not other calibers out there, not other platforms besides the AR - 6.5G seems more finicky.
Link Posted: 5/4/2009 6:10:47 PM EDT
[#20]
Originally Posted By vmpglenn:
Originally Posted By MudBug:
Originally Posted By vmpglenn:
On a more personal note, my experience with 6.5G left me with the impression that the round is finicky. You need to bed the gas block and barrel extension using Loctite, you need to match barrel twist to barrel length and projecticle weight, you have to be careful how you break in the barrels, you need to let the VLD projectiles go to sleep, etc. Frankly, I've never had to do any of this stuff to shoot 6.8SPC accurately. Of course, others may have a much different 6.5 story to tell.



Not true, not true at all.

Neither of my Grendels have any of that done to it and both are fine shooters.

Bill A does all that bedding stuff because he believes it's important. It's not a uncommon practice with AR's built for accuracy, It's been done for years by the high power/DCM crowd, benchrest shooters, and prairie dog smackers because they feel it leads to more consistency in the platform, it has nothing to do with caliber. If one of those guys was building a highpower rifle in 6.8 they would bed the barrel and gas block. I do not do it and both my Grendels are good performers.

And really, how can you say barrel break-in is caliber specific? personally I think it's not needed in any caliber, but those that do believe in it do it regardless of caliber, those same people bedding their 6.8 for highpower just might follow standard break-in also because they feel it's important.

You also need to match barrel twist and bullet weight in any rifle you shoot.

Sorry if this seems off topic, but I won't let BS like this stand without being disputed in a thread is supposed to be the be all, end all on this topic.



That's great that your experience with 6.5G has been much more positive. That's two data points on opposite ends of the spectrum...

Here's an interesting article where Bill Alexander talks about barrel twist in 6.5G (has to do with the extreme variation in ogives on the 6.5 bullets used in Grendel loads), as well as the gas block/extension bedding. There have been threads at 65grendel.com where Bill also talks about these issues. He's even gone so far as to say that certain lengths of barrel should have certain twists to maximize accuracy. There doesn't seem to be a need to do this on 6.8 barrels. I can shoot anything from 85gr to 130gr through my 1:11 twist 6.8SPC barrel with excellent results –– and that's through either my 18" WOA or my 12.5" Cardinal Armory.

Here's a thread on 65grendel.com where Bill talks about using JB paste on Satern match barrels during break-in. He specifically mentions that Grendel has a few peculiarities.

Again, compared to 6.8SPC - not other calibers out there, not other platforms besides the AR - 6.5G seems more finicky.



So Bill A likes to follow strict barrel break-in procedures, how does this have anything to do with a Grendel specific shortcoming? Lot's of people like to follow strict barrel break-in procedures regardless of the caliber they are shooting. This is personal preference akin to a 9mm vs 45 debate that happens on any forum dedicated to guns and has nothing to do with a 6,8 vs 6.5 debate.

As for twist it is a well known principal that the longer the bullet the faster twist rate is required. A 308 optimized for shooting 155 grn bullets will suffer accuracy degradation if you try and shoot the larger bullets though it. a 223 with a 1:12 twist rate may work fine for 55 grn and small bullets but will not stabilize a 77 grn sierra. Bill A is an anal engineer and in the process of looking for performance he has found which twist rates work best with which bullets and offers barrels in different twist rates so YOU can chose based on what you want to shoot. Again, this has nothing to do with 6.8 vs 6.5. It's a universal truth that applies to all calibers.
Link Posted: 5/4/2009 6:17:31 PM EDT
[Last Edit: jjar15] [#21]
My take on part of the 'which should I buy' conundrum.

Number of Gun Manufacturers

The supposed issue of the number of gun manufacturers currently producing 6.X is nonsensical, WRT to choosing a caliber.  You only buy a particular gun from one mfg.  Both calibers are offered by many manufacturers.  It would be silly to not look to see if the gun you want in caliber 6.x is available from one of those many manufacturers, or to not buy an available gun in caliber 6.X, simply becasue there are more mfg of caliber 6.Y.

Replacement Parts

The question of replacement parts is legitimate.  The only caliber specific replacement part is the bolt.  The number of gun mfgs is irrelevant to this point, because most AR mfgs are assemblers.  They dont make their own bolts.  So, how many replacement bolt mfgs are there for each caliber?  That is a relevant question, and an interesting question...

Pretty likely that there are a few 6.8 bolt mfgs distributing their wares amongst the many 6.8 gun manufacturers.  That is a good thing, and an advantage vs the 6.5.  What makes it an even more interesting question is this - the 6.8 bolt is a one-off proposition, as it is based on the obsolete 30 Rem case.  No other currently loaded cartridge shares the 6.8 boltface.  On the other hand, the 6.5 is based on the ubiquitous 7.62x39 and shares its bolt face with that cartridge as well as the PPC family of cartridges, the 6mm AR, the 50 Beowolf, etc.  Yes, there is a difference in the headspace spec between an AA bolt and a generic 7.62x39 bolt, but the direction of that difference permits addressing it with a few turns of a chambering reamer.  In the event of the sudden disappearance of AA and all compatible parts, you could replace a 6.5 bolt with a 7.62x39 after a cheap and easy bit of work.  Or, you could order your 6.5 to have the standard 7.62x39 headspace spec from the get go.  Either path opens the entire 7.62x39/PPC 'support network' to you, if and when you feel the need.  Between the two calibers, frankly its a wash under current circumstances.  Perhaps a slight edge to the 6.5 WRT longevity, as losing compatible replacement bolts would take the complete failure of several calibers instead of just one.

Ammo

Ammo choice is similarly a mixed bag.  There are more factory ammo choices for the 6.8.  More mfgs, and more loads.  The 6.5 is not left completely in the dust here.  Between AA and Wolf you can get match quality ammo (not available for 6.8) down to cheap blaster packs, but there is more diversity available for the 6.8.  And at least for us here in the sticks, 6.8 (Remington, not the good stuff) is available over the counter in some stores.  The 6.5 is pretty much a mail order proposition for factory ammo.  Advantage 6.8.

For those of us that load our own, the situation is reversed.  The 6.5 has more and higher quality components available, from a broader range of manufacturers.  There are more and higher quality bullets available for the 6.5, and those bullets have higher BC and SD than otherwise comparable 6.8 bullets.  Match quality brass is available from Lapua for the 6.5, and the inexpensive Wolf ammo is made with reloadable brass.  Also, 6.5 can be loaded directly from 7.62x39 brass, available from numerous manufacturers, both foreign and domestic.  This is a plus, not only for current circumstances but for the 'longevity' issue as well.  Unlike the 6.8, which has no 'siblings' in the cartridge world, so long as the 7.62x39, .220 Russian or PPC family of cartridges are around, brass will be available for the 6.5.  Advantage 6.5.

Magazines

Currently, three manufacturers make 6.8 mags, and one of those makes 6.5 mags.  Doesnt seem to be a problem with either the quality or supply of the CP mags, but if they go away the 6.8 would have an option.  Advantage 6.8.

Final Analysis

Based on these criteria, its a wash.  Buy what you want.  If you are only going to use factory ammo, and all else is equal for you, get the 6.8.  If you want the most options for handloads and all else is equal for you, get the 6.5.

If you are hugely concerned about near term availability of magazines, and all else is equal for you, get the 6.8.  If you are hugely concerned about the long term availability of replacement parts and ammunition components, get the 6.5.
Link Posted: 5/4/2009 6:25:36 PM EDT
[#22]
Originally Posted By jjar15:Between AA and Wolf you can get match quality ammo (not available for 6.8) down to cheap blaster packs, but there is more diversity available for the 6.8.


Don't forget that Black Hills Ammunition also makes match 6.5 Grendel ammo.

John

| 6.5 Grendel: The Tier One AR Cartridge. |

www.65grendel.com

Link Posted: 5/4/2009 6:30:56 PM EDT
[Last Edit: Cold] [#23]
Link Posted: 5/4/2009 6:58:15 PM EDT
[Last Edit: Zhukov] [#24]
<Off topic comments removed - Z>
Link Posted: 5/4/2009 8:05:13 PM EDT
[#25]
I don't have either caliber yet (18" 6.5 CSS barrel kit on the way) but this topic is always interesting to read because of the heated debates.

I played around the idea of building AR10 in .308 until I learned about the 6.5. Similar trajectories out to 1000 yards, AR15 platform, lighter recoil, and being easier to maneuver were the deciding factors for me to go with the 6.5.

I will probably eventually end up building a 6.8 in the future, but I decided to go with the 6.5 now for the reasons that I am a hand loader and like to experiment (my rifle will probably never shoot factory ammo), the 6.5 is more capable at 1000 yards (not my main objective but why not, since the price is not much more), and why not have something else that is different then the main stream since components are somewhat obtainable now even in todays market..

Now that I stated my opinions I have one question: Why is it always argued that the 6.5 needs a longer barrel to perform? Bill A. and many others at the 65grendel forums seem to favor the 18" to 20" barrels.  It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?
Link Posted: 5/4/2009 9:18:47 PM EDT
[Last Edit: DDriller] [#26]
Originally Posted By jjar15:

[The question of replacement parts is legitimate.  The only caliber specific replacement part is the bolt.  The number of gun mfgs is irrelevant to this point, because most AR mfgs are assemblers.  They dont make their own bolts.  So, how many replacement bolt mfgs are there for each caliber?  That is a relevant question, and an interesting question...

Pretty likely that there are a few 6.8 bolt mfgs distributing their wares amongst the many 6.8 gun manufacturers.  That is a good thing, and an advantage vs the 6.5.  What makes it an even more interesting question is this - the 6.8 bolt is a one-off proposition, as it is based on the obsolete 30 Rem case.  No other currently loaded cartridge shares the 6.8 boltface.  On the other hand, the 6.5 is based on the ubiquitous 7.62x39 and shares its bolt face with that cartridge as well as the PPC family of cartridges, the 6mm AR, the 50 Beowolf, etc.  Yes, there is a difference in the headspace spec between an AA bolt and a generic 7.62x39 bolt, but the direction of that difference permits addressing it with a few turns of a chambering reamer.  In the event of the sudden disappearance of AA and all compatible parts, you could replace a 6.5 bolt with a 7.62x39 after a cheap and easy bit of work.  Or, you could order your 6.5 to have the standard 7.62x39 headspace spec from the get go.  Either path opens the entire 7.62x39/PPC 'support network' to you, if and when you feel the need.  Between the two calibers, frankly its a wash under current circumstances.  Perhaps a slight edge to the 6.5 WRT longevity, as losing compatible replacement bolts would take the complete failure of several calibers instead of just one.

[


It is real simple to open up the bolt face on a 5.56 and make a 6.8 bolt, as it has been done by several companies.  The extractor has to be tweeked but that is not to hard.   IMHO your analysis is off base as there are many more 5.56 bolts than 7.62 x 39.  Headspace should not be an issue as it is with the 6.5
Link Posted: 5/4/2009 9:21:11 PM EDT
[#27]
one of the things that brought me to the 6.8 spc was  I wanted a rifle that what harder hitting then the 5.56 able to take game up to around 400 pound at up to 400 yards, yet at the same time be a very effective round out of a 14" barrel. for me the 6.8 was the anwser

a big plus was visiting the forum and finding the happiest firearm forum on the net
Link Posted: 5/4/2009 9:30:04 PM EDT
[#28]
Originally Posted By GrantMan:
It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?



It wasn't designed that way, it's just the nature of the beast.

Basically because of the high BC of most 6.5 bullets, they retain velocity and performance to a longer range.

so comparing lets say 100 grn bullets in different calibers starting at the same velocity, one caliber uses very high BC bullets and other uses very low BC bullets, you will find the lower BC bullets running out of gas quicker and with a much worse trajectory than the bullet with a high BC.

This is a very simple explanation, so I ask that the real Ballisticians on the forum take it easy on me.

Link Posted: 5/4/2009 9:30:10 PM EDT
[Last Edit: Tim_W] [#29]
Originally Posted By GrantMan:
I don't have either caliber yet (18" 6.5 CSS barrel kit on the way) but this topic is always interesting to read because of the heated debates.

I played around the idea of building AR10 in .308 until I learned about the 6.5. Similar trajectories out to 1000 yards, AR15 platform, lighter recoil, and being easier to maneuver were the deciding factors for me to go with the 6.5.

I will probably eventually end up building a 6.8 in the future, but I decided to go with the 6.5 now for the reasons that I am a hand loader and like to experiment (my rifle will probably never shoot factory ammo), the 6.5 is more capable at 1000 yards (not my main objective but why not, since the price is not much more), and why not have something else that is different then the main stream since components are somewhat obtainable now even in todays market..

Now that I stated my opinions I have one question: Why is it always argued that the 6.5 needs a longer barrel to perform? Bill A. and many others at the 65grendel forums seem to favor the 18" to 20" barrels.  It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?

A short barreled 6.8 will produce velocities much faster than a 6.5 with the same weight bullet and same length barrel.  If you talk about military use, I don't think they will clear houses with a 24" barrel and 20ft doesn't give the G much time to finish fast if it starts out slow. If you want to punch paper at distances over 500 yds a grendel has the advantage because it has so many match bullets to choose from. As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift.
If you move up to the 139gr Lapua there will be a larger difference in drop but the 139 will do better with drift. Velocity makes up for a lot of BC and the 6.8 has the G beat in velocity game with bullets of the same weight  from the same length barrels. The bullet i found to work best from the grendel was the 100gr lapua scenar and would hit 2850fps out of a 22' barrel when pushed to the point of flattening primers with Reloader 10X, your 18" will push that 100grain bullet to apx 2750 and have apx 1392ft lbs energy at 100 yds. The 6.8 will push a 100 gr bullet to apx 3100 from a 22" barrel. 250 fps makes up for a lot of BC. To compare to the 18" barrel you have a 6.8 will have 1667 ft lbs at 100yds.
For hunting and making reliable humane kills on big game the 6.5 or 6.8 do not have enough energy to take game much past 300yds even though both camps have taken elk at near 400 yds so high BC bullets will poke holes in things at 1000yds but that does not mean they have enough energy left at that range to make humane kills.

Link Posted: 5/4/2009 11:28:39 PM EDT
[#30]
Originally Posted By Tim_W:
Originally Posted By GrantMan:
I don't have either caliber yet (18" 6.5 CSS barrel kit on the way) but this topic is always interesting to read because of the heated debates.

I played around the idea of building AR10 in .308 until I learned about the 6.5. Similar trajectories out to 1000 yards, AR15 platform, lighter recoil, and being easier to maneuver were the deciding factors for me to go with the 6.5.

I will probably eventually end up building a 6.8 in the future, but I decided to go with the 6.5 now for the reasons that I am a hand loader and like to experiment (my rifle will probably never shoot factory ammo), the 6.5 is more capable at 1000 yards (not my main objective but why not, since the price is not much more), and why not have something else that is different then the main stream since components are somewhat obtainable now even in todays market..

Now that I stated my opinions I have one question: Why is it always argued that the 6.5 needs a longer barrel to perform? Bill A. and many others at the 65grendel forums seem to favor the 18" to 20" barrels.  It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?

A short barreled 6.8 will produce velocities much faster than a 6.5 with the same weight bullet and same length barrel.  If you talk about military use, I don't think they will clear houses with a 24" barrel and 20ft doesn't give the G much time to finish fast if it starts out slow. If you want to punch paper at distances over 500 yds a grendel has the advantage because it has so many match bullets to choose from. As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift.
If you move up to the 139gr Lapua there will be a larger difference in drop but the 139 will do better with drift. Velocity makes up for a lot of BC and the 6.8 has the G beat in velocity game with bullets of the same weight  from the same length barrels. The bullet i found to work best from the grendel was the 100gr lapua scenar and would hit 2850fps out of a 22' barrel when pushed to the point of flattening primers with Reloader 10X, your 18" will push that 100grain bullet to apx 2750 and have apx 1392ft lbs energy at 100 yds. The 6.8 will push a 100 gr bullet to apx 3100 from a 22" barrel. 250 fps makes up for a lot of BC. To compare to the 18" barrel you have a 6.8 will have 1667 ft lbs at 100yds.
For hunting and making reliable humane kills on big game the 6.5 or 6.8 do not have enough energy to take game much past 300yds even though both camps have taken elk at near 400 yds so high BC bullets will poke holes in things at 1000yds but that does not mean they have enough energy left at that range to make humane kills.



Thanks, that does make sense. I am assuming the 70" less drop is at 1000 yards?
Link Posted: 5/4/2009 11:52:30 PM EDT
[#31]
Originally Posted By GrantMan:
Originally Posted By Tim_W:
Originally Posted By GrantMan:
I don't have either caliber yet (18" 6.5 CSS barrel kit on the way) but this topic is always interesting to read because of the heated debates.

I played around the idea of building AR10 in .308 until I learned about the 6.5. Similar trajectories out to 1000 yards, AR15 platform, lighter recoil, and being easier to maneuver were the deciding factors for me to go with the 6.5.

I will probably eventually end up building a 6.8 in the future, but I decided to go with the 6.5 now for the reasons that I am a hand loader and like to experiment (my rifle will probably never shoot factory ammo), the 6.5 is more capable at 1000 yards (not my main objective but why not, since the price is not much more), and why not have something else that is different then the main stream since components are somewhat obtainable now even in todays market..

Now that I stated my opinions I have one question: Why is it always argued that the 6.5 needs a longer barrel to perform? Bill A. and many others at the 65grendel forums seem to favor the 18" to 20" barrels.  It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?

A short barreled 6.8 will produce velocities much faster than a 6.5 with the same weight bullet and same length barrel.  If you talk about military use, I don't think they will clear houses with a 24" barrel and 20ft doesn't give the G much time to finish fast if it starts out slow. If you want to punch paper at distances over 500 yds a grendel has the advantage because it has so many match bullets to choose from. As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift.
If you move up to the 139gr Lapua there will be a larger difference in drop but the 139 will do better with drift. Velocity makes up for a lot of BC and the 6.8 has the G beat in velocity game with bullets of the same weight  from the same length barrels. The bullet i found to work best from the grendel was the 100gr lapua scenar and would hit 2850fps out of a 22' barrel when pushed to the point of flattening primers with Reloader 10X, your 18" will push that 100grain bullet to apx 2750 and have apx 1392ft lbs energy at 100 yds. The 6.8 will push a 100 gr bullet to apx 3100 from a 22" barrel. 250 fps makes up for a lot of BC. To compare to the 18" barrel you have a 6.8 will have 1667 ft lbs at 100yds.
For hunting and making reliable humane kills on big game the 6.5 or 6.8 do not have enough energy to take game much past 300yds even though both camps have taken elk at near 400 yds so high BC bullets will poke holes in things at 1000yds but that does not mean they have enough energy left at that range to make humane kills.



Thanks, that does make sense. I am assuming the 70" less drop is at 1000 yards?


Yes
Link Posted: 5/5/2009 12:01:13 AM EDT
[#32]
Cold,

"The barrels are caliber specific as I see it, since not any old barrel will just work for either, maybe you meant to include this but did not, as you wrote a fairly in depth post, however more then a few companies make 6.8 barrels, off the top of my head, I can count no less then 7, and several of those companies make barrels for many others."

Certainly a barrel is caliber specific, and I did consider including it.  In the end I didnt for a few reasons, all of which seem to moot the point WRT the topic of the thread:

1)  For most shooters, a barrel is not a 'replacement part'.  Most would consider a 'replacement part' to be a low cost part that saves the use of a high cost part, i.e the $50 bolt that keeps the $400 barrel running, rather than the other way around.  Also, few shooters will ever wear out a barrel.

2)  Those few shooters for whom a barrel is genuinely a consumable part know where to get barrels and they can get any caliber they want.

3)  There are lots of barrel makers who will do both calibers, so if you find yourself in need of a new barrel you are essentially back at the 'which caliber do I buy' stage of the game.

"SSA makes match ammo by all accounts, I guess save yours... you have not shot it obviously. Black Hills makes match 6.8 ammo for those with the proper creds."

I didnt mean any slight to any of the 6.8 ammo makers.  By match ammo, I meant mtach grade components assembled with match grade consistency.  Not "Golly that shoots well at 100 yards" but "That wins matches at 1000 yards".  The 6.5 has Lapua brass available.  AA puts that together with match bullets (Scenar, SMK, etc).  And Bill A is finicky enough that we can be assured it is assembled with high tolerances.  I do not believe that any brass of that quality is available in 6.8.  I dont know what  bullets the others use, or if they are aiming for high qulaity commercial or true match spec.  I am open to additional references...

"Otherwise, I think thats a fair assessment of things at this point, will see what more 2009 holds."

Thank you.

DDriller,

"It is real simple to open up the bolt face on a 5.56 and make a 6.8 bolt, as it has been done by several companies."

It isnt real simple.  Doing it right involves redoing the heat treat, etc.  That is tricky business.  To the extent that it can be done, it can be done as easily from .223 to 6.5 as from .223 to 6.8.

Link Posted: 5/5/2009 12:06:29 AM EDT
[#33]



Originally Posted By Tim_W:



Originally Posted By GrantMan:

I don't have either caliber yet (18" 6.5 CSS barrel kit on the way) but this topic is always interesting to read because of the heated debates.



I played around the idea of building AR10 in .308 until I learned about the 6.5. Similar trajectories out to 1000 yards, AR15 platform, lighter recoil, and being easier to maneuver were the deciding factors for me to go with the 6.5.



I will probably eventually end up building a 6.8 in the future, but I decided to go with the 6.5 now for the reasons that I am a hand loader and like to experiment (my rifle will probably never shoot factory ammo), the 6.5 is more capable at 1000 yards (not my main objective but why not, since the price is not much more), and why not have something else that is different then the main stream since components are somewhat obtainable now even in todays market..



Now that I stated my opinions I have one question: Why is it always argued that the 6.5 needs a longer barrel to perform? Bill A. and many others at the 65grendel forums seem to favor the 18" to 20" barrels.  It was my understanding that the 6.5 Grendel was designed to start of slow and finish fast. Are we comparing muzzle velocities only or is there something else I am overlooking?


A short barreled 6.8 will produce velocities much faster than a 6.5 with the same weight bullet and same length barrel.  If you talk about military use, I don't think they will clear houses with a 24" barrel and 20ft doesn't give the G much time to finish fast if it starts out slow. If you want to punch paper at distances over 500 yds a grendel has the advantage because it has so many match bullets to choose from. As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift.

If you move up to the 139gr Lapua there will be a larger difference in drop but the 139 will do better with drift. Velocity makes up for a lot of BC and the 6.8 has the G beat in velocity game with bullets of the same weight  from the same length barrels. The bullet i found to work best from the grendel was the 100gr lapua scenar and would hit 2850fps out of a 22' barrel when pushed to the point of flattening primers with Reloader 10X, your 18" will push that 100grain bullet to apx 2750 and have apx 1392ft lbs energy at 100 yds. The 6.8 will push a 100 gr bullet to apx 3100 from a 22" barrel. 250 fps makes up for a lot of BC. To compare to the 18" barrel you have a 6.8 will have 1667 ft lbs at 100yds.

For hunting and making reliable humane kills on big game the 6.5 or 6.8 do not have enough energy to take game much past 300yds even though both camps have taken elk at near 400 yds so high BC bullets will poke holes in things at 1000yds but that does not mean they have enough energy left at that range to make humane kills.



That sounds real good, but a little research reveals that that 6.8 GSC bullet has a .505 BC at 3800 fps...not at 3000fps. And GSC has a 6.5mm bullet that has a BC of .655 to .586 from 3300-2650. Using it would also add fps to the Grendel number since it's a low friction bullet....so, no, using comparable bullets the 6.8 will not out distance the 6.5.



But take what I say with a HUGE grain of salt. Make it a mountain. After all, I do own a Grendel, which makes anything I type tainted with a stench of prejudice and secret motives.





 
Link Posted: 5/5/2009 12:40:02 AM EDT
[#34]
Originally Posted By Cold:Black Hills makes match 6.8 ammo for those with the proper creds.


Nope. Perhaps you meant made one small batch at one point in time for one organization? This from the personal testimony of a certain BH representative.

John

| 6.5 Grendel: The Tier One AR Cartridge. |

www.65grendel.com

Link Posted: 5/5/2009 1:25:26 AM EDT
[#35]
My second pet peeve regarding this topic involves the discussions of performance.  Especially those framed as a comparison between two cartridges - either between the two that are the topic of the thread, or between one of them and some vaunted standard.  The typical fan boi tactic is to compare apples to oranges.  Or apples to cucumbers.  Or apples to vacuum cleaners.  Valid comparisons must hold 'all else equal'.  Anything different is worthless nonsense.

Both sides do it.  Some knowledgable posters on this site who otherwise make valuable contributions do it.  It is crap.  Absolute crap.  It is dishonest and adds to the confusion and the controversy.

Example 1:  "The 6.5 has the ballistics of a .308, with half the recoil!"

Absolute nonsense.  Achieved by comparing a light for caliber, low BC .308 loaded to much lower than optimum velocity against a high BC 6.5 max load, and by only looking at trajectory.  Well, there are much better bullets for the .308 than 147gr ball, a bullet of that weight can be pushed a lot faster than 2600 fps in a .308, and 'ballistics' includes energy and terminal effect as well as trajectory.  There are plenty of .308 loads that will smoke any conceivable 6.5 at all of those.

Example 2:  From this very thread.  "As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift."

Yes, competition shooters would use the best bullet.  So why does this example use the best bullet for a 6.8, and a comparatively mediocre bullet for the 6.5?  And why does this example use untested 'wildcat' handload data for the 6.8, and conservative published factory data for the 6.5?  Because somebody has an agenda.

Frankly the BCs published for GS bullets seem a bit ... optimistic.  But if a poster is going to use GS bullets to fluff up his 6.8 - a caliber that never sees SPC compatible bullets with BCs over .500 from any other source - then why doesnt he use a GS bullet for his 6.5 comparison load?  Why does he use a 123 gr SMK instead?  Because GS has a 101gr 6.5 with an advertised .592 BC, and a 110gr claimed to run .655.  Kind of leaves that paltry .505 for the 6.8 in the dust, doesnt it?

And unpublished data from an ARFCOM heavy puts a 100 gr out of a 6.5 at 2900 fps.  An analagous load for the 110 would run 2800 fps.  Run those velocities with the corresponding GS BCs thru Quick Target, and you will quickly see why the poster in question was holding a Granny Smith in one hand and a Valencia in the other.

Comparisons must be of comparable bullets, from comparable barrels, at comparable safety factors for pressure.  Anything else is applesauce.
Link Posted: 5/5/2009 3:12:44 AM EDT
[Last Edit: Tim_W] [#36]
Originally Posted By jjar15:
My second pet peeve regarding this topic involves the discussions of performance.  Especially those framed as a comparison between two cartridges - either between the two that are the topic of the thread, or between one of them and some vaunted standard.  The typical fan boi tactic is to compare apples to oranges.  Or apples to cucumbers.  Or apples to vacuum cleaners.  Valid comparisons must hold 'all else equal'.  Anything different is worthless nonsense.

Both sides do it.  Some knowledgable posters on this site who otherwise make valuable contributions do it.  It is crap.  Absolute crap.  It is dishonest and adds to the confusion and the controversy.

Example 1:  "The 6.5 has the ballistics of a .308, with half the recoil!"

Absolute nonsense.  Achieved by comparing a light for caliber, low BC .308 loaded to much lower than optimum velocity against a high BC 6.5 max load, and by only looking at trajectory.  Well, there are much better bullets for the .308 than 147gr ball, a bullet of that weight can be pushed a lot faster than 2600 fps in a .308, and 'ballistics' includes energy and terminal effect as well as trajectory.  There are plenty of .308 loads that will smoke any conceivable 6.5 at all of those.

Example 2:  From this very thread.  "As all competition shooters load their own for best accuracy and would use the best bullets obtainable to do so then compare the best 6.5 bullet loaded to the max the grendel can push it and load a .277 GS 105gr (BC =.505) bullet to the max in a 6.8(3000fps from a 20" barrel). If you use a 123gr Lapua Scenar (BC .547)at 2570fps from a 20" barrel(what Bill A says is the max and never go over it) the 105 bullet will have apx 70" less drop than the 123 and apx 3" less drift."

Yes, competition shooters would use the best bullet.  So why does this example use the best bullet for a 6.8, and a comparatively mediocre bullet for the 6.5? it was used the show the quoted post that not all 6.5 bullets outshoot all 6.8 bullets the way you guys would want it to seem. The 123gr Lapua Scenar is mediocre? You obviously have not shot the Lapua, I use it in a 6.5-08 AI, 260 and Creedmoor and prefer it  over the 139s and 140s when shooting at unknown range due to the flatter trajectory. And why does this example use untested 'wildcat' handload  data for the 6.8, and conservative published factory data for the 6.5?  Because somebody has an agenda.  I tested the load and the pressure the same way Bill A tested his loads(pressure trace) and pressures in front of 4 others.  Bring any Grendel AR15 you want loaded to the max but not blowing primers and and put it up against Constructors 6.8 of the same length barrel and same bullet weight and you will lose the velocity race.

Frankly the BCs published for GS bullets seem a bit ... optimistic.  Have you ever shot 1, just 1? have you tested any for BC? 6.8 - a caliber that never sees SPC compatible bullets with BCs over .500 from any other source - then why doesnt he use a GS bullet for his 6.5 comparison load?  Why does he use a 123 gr SMK instead? HUH? who said anything about a SMK? Because GS has a 101gr 6.5 with an advertised .592 BC, and a 110gr claimed to run .655.  Kind of leaves that paltry .505 for the 6.8 in the dust, doesnt it?  I would say a faster bullet would leave the other in the dust as you put it, as in behind the faster bullet kind of like the car that is faster leaves the slower one in the dust LOL. The grendel guys are always saying "we could make a mag that feeds well" yes but you haven't, "we could shoot GS bullets" yes  but you haven't "we could get that much vel."  I doubt it,  Talk is cheap. When used for hunting or combat the 6.5 and 6.8 are  300yd cartridges and in that 300yds the 6.8 smokes the Grendel. To be used in combat the rifle must be reliable, the G failed the full auto test, can the G be used in belts or links? I doubt it, yep that is my opinion

And unpublished data from an ARFCOM heavy puts a 100 gr out of a 6.5 at 2900 fps.  An analagous load for the 110 would run 2800 fps.  Run those velocities with the corresponding GS BCs thru Quick Target, and you will quickly see why the poster in question was holding a Granny Smith in one hand and a Valencia in the other. In what length barrel? 24-26" "C"  has hit that velocity with a Banshee and a 22" but could not get close to that with a grendel 20" 10 twist 5R Mike Rock barrel although he did blow a case trying. The 6.8 will push a 110 to 2900 from a 20" barrel at 58000 psi. The Grendel shoots at 54000 PSI set by Bill A. As he is one of the 2 guys that developed the cartridge. 3 years ago right here on this site Grendelizer any everyone else screamed bloody murder everytime someone tried to push the G a little. I believe Grendelizer said "he will push it and the test are going great then poof we will never hear from him again after the rifle blows"  
Most of SSAs loads run 53000 in a saami 6.8 chamber but only run 46000 in a SPCII or DMR, so we can load above SSAs loads and still remain at a safe 58000psi which is safe in the 6.8 because the bolts have more material at the lugs and are stronger because of it.
.

Comparisons must be of comparable bullets, from comparable barrels, at comparable safety factors for pressure.  Anything else is applesauce.

Comparable length barrels yes but, who says we have to use a 8 twist 6 groove barrel when some of us know how to design better performing barrels. The 5.56 m193 and m855 loads develop 58000psi. Every cartridge has it's own pressure limit. Bill set the G limit at 54000psi, what Bill thinks is safe for his G has absolutly no bearing on the 6.8 and the pressure it is used at. Bill and Arne are wildcatters that kind of standardized a cartridge it is not a SAAMI approved cartridge like then Rem 6.8x43 SPC is.  
You guys have been posting the same  4 year old charts of the 6.8 fmj VS the 6.5s 123gr Lapua load for the last 4 years, just thought we would do the same to you.

Performance wise-If you punch paper at long distance the 6.5 has an edge because there are more match bullets with a higher BC.  For a hunting rifle they are close but the 6.8 has the edge because of better terminal performance and really more hunting bullets in the usable range up to130gr.
For a military rifle the 6.8 wins easily for many reasons, the biggest is better terminal performance from lengths of barrels commonly used in combat.

Availability- goes to the 6.8, almost ever major manufacturer builds a 6.8. there is no license needed to build it. There are more parts and accessories avail and from many sources not just 1.
LMT, LWRC, CMT, DMPS, Armalite. I.T.S. and possibly PWS make 6.8 bolts, PRI, Barrett and CP make 6.8 mags.
1 company in Fla. makes all the Grendel bolts, 7.62X39 bolts will not work in the Grendel without a gunsmith setting the headspace by lengthening the chamber .012"
1 company, CP makes all the grendel mags. Grendel brass is apx 30% more expensive than SSA 6.8 brass.


Link Posted: 5/5/2009 5:50:16 AM EDT
[Last Edit: Cold] [#37]
Link Posted: 5/5/2009 5:58:59 AM EDT
[Last Edit: Cold] [#38]
Link Posted: 5/5/2009 6:55:40 AM EDT
[Last Edit: Zhukov] [#39]
<Please keep posts on topic about the merits of 6.5/6.8 - Z>

Link Posted: 5/5/2009 10:49:14 AM EDT
[Last Edit: Zhukov] [#40]
<Please keep posts on topic about the merits of 6.5/6.8 - Z>


Link Posted: 5/5/2009 7:20:18 PM EDT
[Last Edit: hi-tech-rancher] [#41]
How about if I sum things up this way?

1) Both the Grendel and 6.8 SPC are shooting heavier projos than the 5.56, and both carry higher energy to the target at ranges we all consider "reasonable," for hunting, targets or SHTF.  Let's (for the sake of argument) exclude extremes of range, like 1000 yards.  That is reserved for competition.  If that is specifically what you do, buy a .308, .260 Remington or 6.5 Grendel .  That is not the milieu for the 6.8 SPC.

2) Both cartridges can send a bullet downrange at somewhere around 2450 - 2650 FPS, but only the 6.8 SPC has practically eclipsed the 3000 FPS mark, and that was in a 16 inch barrel.  This is not a wildcat....I repeat, NOT a wildcat .     A man can simply buy SSA 85 grain TSX's and shoot them tomorrow morning at the range in any one of about eight 6.8 SPC guns.  When you consider this is done with a Barnes bullet, the killing performance for a hunter, is far beyond that of anything the 5.56 can currently muster.  When you further consider you only need a 16 inch barrel to do so, things get that much more interesting, because you only need one rifle for many different tasks, and not that many of us has money for 12 rifles.  The Grendel is too specialized to allow for all these versatile uses in short barrels, using several bullets, with just one twist rate, and barrel.

3) Take number 1 and 2 above and consider that, even if both cartridges are roughly similar in performance on paper, only the 6.8 SPC can achieve these things in a 6.5 lb, lightweight M4 profile CAR-style gun, still keeping 1MOA , out to 300 yards, and in skilled hands, farther.  I own one, I have shot silhouettes at 500 with nothing but an unmagnified Eotech,  and I will personally show it to any of you that doubts this.

4) Take 1, 2, and 3, and consider that there are many more manufacturers making these 6.8 SPC guns in all of the various styles, profiles and configurations we came to know for 5.56 over the years.

So, it has very little to do with BC, sectional density, 1000 yard drop, dope, Lapuas, Creedmores, or Aardvarks.  The real question is, which ofthese 6X's which are so similar in so many ways, is practically advanced, evolved and available?

I believe the answer is 6.8 at this time.  That may change but right now, the market seems to have glommed on to the 6.8 and I am quite sure there are reasons for this.
Link Posted: 5/5/2009 7:43:00 PM EDT
[#42]
hi-tech-rancher,

This is a question, not an accusation. I'm asking cuz I don't know.

I know the original 6.8 spc has SAAMI specs, and is therefor not a wildcat, but aren't the new 6.8 SPC II chambers different than the SAAMI spec chamber?
Link Posted: 5/5/2009 9:03:31 PM EDT
[Last Edit: Tim_W] [#43]
Originally Posted By MudBug:
hi-tech-rancher,

This is a question, not an accusation. I'm asking cuz I don't know.

I know the original 6.8 spc has SAAMI specs, and is therefor not a wildcat, but aren't the new 6.8 SPC II chambers different than the SAAMI spec chamber?

It has a longer leade, shoots the same ammo, same case, just like a 5.56 shoots 223 ammo.
BTW I am all for dropping the Remington name from the 6.8SPC, let Remington keep their name and screwed up SAAMI specs.
Link Posted: 5/6/2009 12:06:49 AM EDT
[#44]
Originally Posted By MudBug:
hi-tech-rancher,

This is a question, not an accusation. I'm asking cuz I don't know.

I know the original 6.8 spc has SAAMI specs, and is therefor not a wildcat, but aren't the new 6.8 SPC II chambers different than the SAAMI spec chamber?


Mudbug, not an unreasonable question....

TIm W (as usual) has it right.  The 6.8 SPC , as it was originally released, was promoted bu Remington as having the capability of launching a 115 grain projectile at 2800 FPS, from a 24" barrel.   The very sad fact is that they could never reproduce this performance , after their selection of powder was shown to be temperature sensitive, and after they selected the twist rates used for .270 Winchester.  It is astonishing, that Remington didn't know that "varmint weight" bullets of 110 and 115 grains in .277 might just use a slower twist, despite this being consistent with all the laws of physics, and current ballistics theory......but wait...,maybe in their zeal to make an AR hunting caliber, they just simply overlooked this small factor.

If you look at the original Murray chamber designed by the AMU,  It has a longer leade than the SAAMI chamber.    SAAAMI is not without blame here.  They just figured Remington knew what they were doing, so they used the chamber drawings and nominal pressure values for the cartridge that Remington gave them....which were WRONG.  

So, here we are in 2009.  Regular shooters , especially Harrison Beene of AR Performance, and Art Kalwas of SSA, went back to the drawing board, and re-invented the 6.8 SPC cartridge.  It is one of the great stories of individual ingenuity and perseverance..  Remington gave up....yeah,  they threw in the towel, when they couldn't make their velocity claim.  They just blew this cartridge off, and figured it would die on the vine.  BOY , WERE THEY WRONG.

So, while I can see that some would claim that the 6.8 SPC is a wildcat, nothing could be further from the truth.  There are at least 4 companies manufacturing the cartridge, but because non-corporate entities KICKED THE ASSES of the big names that should have known better, these companies  all are still playing it safe, and sticking to totally laughable SAAMI specs.  One very bright note is that Noveske, is now ready to release their 12 twist, polygonal, Mod O chamber barrel.  Why is this noteworthy??? Because Noveske is not releasing this barrel to shoot Hornady Vmax's loaded to an anemic 2550 FPS!!!  They are committed to optimal performance, and they know that the cartridge is now capable, if shot in the right barrel, of 3160 FPS from a 16" barrel.  Why would they release anything that could not shoot the pinnacle of  the available performance??

It is a real shame that SAAMI has NEVER, EVER once come to this forum to post ANYTHING, in support of their specs, to tell us why THEIR chamber should b remain the market gold-standard, in spite of the fact that it is now obsolete, and will forever leave the market only to be relegated to a collector's item.  

Sigh.....
Link Posted: 5/6/2009 12:49:31 AM EDT
[#45]
So if someone had an old SAAMI spec rifle, and they got a hold of some new improved 6.8 SPC II ammo and shot it, what would happen?
Link Posted: 5/6/2009 1:01:53 AM EDT
[#46]
Originally Posted By MudBug:
So if someone had an old SAAMI spec rifle, and they got a hold of some new improved 6.8 SPC II ammo and shot it, what would happen?


Depends on the ammo (e.g. 115gr OTMs are .277, but 110gr Accubonds are actually .276), but typically the same thing that would happen if someone got ahold of a .223 chambered rifle and shot 5.56 through it. Or if someone got ahold of a tight-chambered .308 like an LR308 and shot 7.62x51 through it. SAAMI rifle, non-SAAMI ammo. Doesn't mean the non-SAAMI ammo is inherently dangerous...
Link Posted: 5/6/2009 2:09:19 AM EDT
[#47]
Originally Posted By MudBug:
So if someone had an old SAAMI spec rifle, and they got a hold of some new improved 6.8 SPC II ammo and shot it, what would happen?


Glenn has it about right.  You might get ejector swipes, or popped primers, similar to what would happen if you shot 5.56 NATO rounds through a .223 chambered gun.

The thing that gets me is this:

Do you think SAAMI would tell shooters that  all AR-15's should be chambered in .223 Remington, and that you should NOT shoot 5.56 NATO ammo in such rifles?  Do you think that manufacturers of AR-15 rifles, in 2009, would release a .223 Remington chambered rifle to the market?  I certainly do not.

Why then in 2009, do we still have ANYONE manufacturing 6.8 SPC rifles with SAAMI chambers, 10 twist, rifling or ammo manufacturers limited to COAL of 2.26"?  The only answer that is possible, is sheer ignorance.  This whole story reminds me of one other analogy:

Let's say that All 12 gauge shotguns were released as 2.75" chambers.  Then, someone had the bright idea of lengthening the chamber to 3 inches.  But SAAMI, and others told them they were crazy, and that this would be a "wildcat."  But, these innovators persisted, and the 3 inch magnum was born, only to overtake the entire waterfowling world by storm, until that became the "top notch."  After that, nobody released a serious waterfowling gun without a 3 inch chamber, because after all, you could still shoot the more anemic 2.75" cartridges in that chamber if you wanted, but your gun was now capable of the top performance.   After that happened, anyone shooting a 3 inch magnum was shooting a wildcat???? ....hardly.

I think you will see the SAAMI chamber simply whimper off into the ash heaps of history.  SAAMI has left a tarnish on their reputation with this whole chapter by staying mute.  They could at least have said something.... anything....when they realized that this cartridge was being revised well beyond what they thought was possible within their "specs."  I am still dumbfounded that they have never again said a word about the 6.8 SPC.  So, as we stand now, "SAAMI specs" as it is currently defined, mean absolutely nothing, and whatever it is that you see defined by the people that advanced this cartridge are now the "specs."   We would have loved to have the credibility of SAAMI in this corner, but they decided to stay with Remington guidance, which was faulty from the start.

Guys like SSA, ARPerformance, Titan Armory, and others know exactly what the specs are and should be.....  hopefully someday SAAMI will revise the specs based upon their recommendation.
Link Posted: 5/6/2009 2:38:07 AM EDT
[Last Edit: MudBug] [#48]
Back when I got my first Grendel, a lot of the 6.8 guys were making a big deal about the fact that it had a SAAMI cert and the Grendel didn't. They also talked smack about Bill A for not seeking one. Bill A basically said something like "It's too much of a hassle, you have to be one of the big boys, and it doesn't really mean that much, the Grendel will live or die on it's performance.".

Kinda odd that the same SAAMI organization that many in the 6.8 praised as the reason the Grendel would never be anything is what almost killed the 6.8 spc.
Link Posted: 5/6/2009 10:59:23 AM EDT
[Last Edit: Zhukov] [#49]
You know what they say, what doesn't kill you only makes you stronger.






This has been a very informative thread, and the conclusion I've drawn from it is as follows.





If I am target shooting out of an AR-15 500-1000yd out, I'd opt for a 6.5 Grendel. The long range performance really makes it an attractive cartridge and all the B.C. S.D. etc. stuff reinforces its use in that application


.


Hunting inside of 300yd, I'd get a 6.8 SPC more so out of convenience than impressions about its performance over the Grendel. I don't know enough about the mag issues I've heard mention of so I won't comment on that. Bottom line I can walk into any local 2nd amendment center and purchase a 6.8 off the rack. Not necessarily a DMR/SPC II chambered one but they are avaliable nonetheless, as well as ammunition. I've yet to see a 6.5 Grendel rifle in person, although I HAVE seen 6.5 Grendel for sale. Nice long pointy bullets.





<Please keep posts on topic about the merits of 6.5/6.8 - Z>
Link Posted: 5/6/2009 12:52:19 PM EDT
[Last Edit: Zhukov] [#50]
<Please keep posts on topic about the merits of 6.5/6.8 - Z>
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