I'm thinking about getting an AR in a non-.223 flavor before the panic buy later this year. I have all the guns I need, but wouldn't mind having a gun that's a true range toy that could also hunt deer. I've done a lot of reading of all of the threads, I know about the trajectories (fairly similar between 308 and 6.5 grendel). This would be primarily for having fun at the range and maybe deer hunting. I want a 20" upper.

I'm trying to spend <$1300 on the gun. So there are a few options. I was originally dead set on a DPMS GII Hunter 308/ Remington R25 .308 or .260 which costs around $1250. However, for the same price, I could build a 6.5 grendel with a matching bolt shilen barrel (1). (could even get the side cocking upper if I wanted(2)). I also have a line on a used Radical Firearms 20" ar for less.

Any thoughts on 308 vs 6.5 grendel for having fun at the range and deer hunting? Are the 6.5's going to have issues with loading? How much accurate will an ar with a matched bolt shilen(3) be than a DPMS G2 hunter? Assuming this deal on the used Radical comes through, is it worth thinking about? Honestly, they both seem like good options...how do I pick one.


----------
(1) I live in MD so any ar-15 based rifle I get needs to have a HBAR. 308's are GTG in any barrel weight
(2) I'm a leftie, so right side charging handle isn't any problem. I'd get the Raptor Charging handle anyway, I already only need a bolt carrier (not a bolt), so side cocking is an option. The only bad part about this is I lose commonality of parts with my other AR-15, which is only a problem if they start banning ar-15 parts.
(3) Assuming I build it correctly.

I would get the AR15 in 6.5 Grendel, which is what I have personally done.

Keep in mind that I have owned 5 different AR10s/LR-308s/LR-260s.

I still have my custom .260, but it's in pieces and has been for over a year now.

All I seem to be interested in is building more 6.5 Grendels.  .308 is totally out for me. Sold my dies, brass, and bullets.

I haven't loaded for the .260 Rem in a long time, and I can only hand load for it, no factory ammo will go near it.

I would avoid the Radical Firearms based on reviews I've seen here where barrels came untorqued during fire, and I just can't take an AR15 seriously at their price points.  Something is being cut somewhere.

All your parts are common with standard AR15s except:

Barrel
Bolt
Mags

I like the GII, but I'm personally only considering the $2500 Mega SF MA-TEN at this point for some other chambering.  I wish I could replace my DPMS LR receiver set with the MEGA SF MA-TEN and then be done with the larger caliber stuff for my dedicated ELR rifle, where I need to engage targets from 1200-1600yds.

I'm waiting on my second Grendel build parts to come in. I do have an Aero .308, fun to shoot for me and my son but my wife and daughter won't touch it. They will shoot any AR15 based caliber though. I think for what you want to do, the 6.5G is a better choice as well. I'm debating some serious gun and caliber reductions and have more multi-use guns like the 6.5G.

I would avoid Radical.

I've been deer hunting for years with a bolt 308 and never found it lacking so I first tried hunting with an Fal, but never achieved acceptable scope mounting. Then a Gap mod Armalite which was sub 1/2", but way to heavy for any stalking. Next was another Armalite 16" Carbine which was no joy to shoot. Then, with much apprehension I asked my dealer to bring in a G2 recon 308. I've only had it for a little over a week and we have been having monsoon rains, so my range time has been limited with a total of just over 200 rds fired. First, it is light enough to hunt with and they have managed the recoil to where I actually enjoyed shooting it from a bench and was sad when the rains came. Trigger is a nice two stage match trigger and I will not replace it with a "G" as 5" palm size groups at 100yds were easy with a red dot, and right at 1" with a hunting scope in a LaRue mount. There have been no failures of any kind, and I realize that 200 rds is not a test of anything, but I would feel really good about deer hunting with this rifle. I hope that you get a chance to handle one. Regards

308 GII no contest.

I have an Aero Precision in 308 and love it.  Shoots WAY sub-MOA and is a legit cartridge for anything walking this continent that won't actually consume you should you fail (brown, griz bear).

Anyhow - my next build is almost certainly going to be another Aero Precision and this time in 7mm-08.

I say go with a 308-based gun.  YMMV but my 308 shoots everything from 110gr handloads to 180gr stuff.  Not sure you have that much selection range in the Grendel or not?  I highly doubt you have 70 grains' worth of bullet range.

Every load I have seen published for the 6.5 Grendel indicates a 24" bbl.  That's fine if you're going to use a tube that long.  If you are, though why not do an AR-10 with a 20" bbl in 308?  308 loads often show 24" of bbl as well BUT it still hits plenty hard out of 20".  If you're sold on a shorter bbl like 18" (plus muzzle device for 20" total) you really need to look at people's chrono'd loads at that bbl length - the energy you get from 6.5 over 223 might or might not still be worth it to you.

Grendel's going to require mags, bbl and bolt (7.62x39 iirc) specific to it.  I'd be much more tempted to do an AR-15 in something that was a bbl-only swap like 25-45 Sharps.  

6.8 SPC will do what you're looking for as well.  Like the Grendel it will require bolt, mags and bbl.  My experience was I saw less velocity loss with an 18" bbl - it still hit plenty hard.  Bullet weight range is a somewhat narrow window but really the 95gr Barnes TTSX is the only one you'll ever need...  Accurate?  Check.  Pigs?  Check.  Deer?  Check.

If you do Aero Precision I recommend buying their M5E upper kit, a lower and their lower parts kit (has longer take-down pins).  Swap in whatever trigger you want.  The BCM Gunfighter AR-10 charging handle works great.  YMMV...

Sometimes information or lack thereof is lacking in regards to ballistics. While the .308 has been proven time and time again and still is a viable caliber, the OP needs can be satisfied with something other than a large framed AR. Actual data as listed in the volume II book available at AA is an eye opener. Factor in weight, recoil and handling of the weapon, the 6.5G is more enjoyable to shoot and increases potential effectiveness.

Edit to add, the vol II book has data from various barrel lengths.

I contemplated this same question in 2009 betwen AR-10 and 6.5 Grendel.  I went with the 6.5 Grendel first with a 16" barrel as I was expecting to go on a Texas hog hunt.  A coworker bought a 24" AA 6.5 Grendel the same year and  we each learned the other bought a 6.5 Grendel on a gun forum.  I started shooting long range with this friend and bought a 20" 6.5 Grendel.  After he shot my 16" Grendel he has added a 18" 6.5 Grendel.  

From reading the gun forums I'd speculate the best selling 6.5 Grendel barrels are 18".  The next common would be about an even split between16" and 20".  I believe the 24" 6.5 are becoming less popular unless the primary role is bench rest.  My Friend has taken numerous antelope mostly with 120 grain Nosler Ballistic Tip hunting bullets.  His longest kill with the 24" 6.5 Grendel was over 500 yards.  My Friend is retired military and LE and can ethically hunt at that distance.

Don't believe the threads that say you need a long 24" barrel in the 6.5 Grendel, the 20" and shorter barrels are very effective for being an intermediate cartridge in an AR-15.   Given that the majority of hunters shoot at 350 yards or less this is well within the range of the 6.5 Grendel.  Add in the capability of target shooting out to 1000 yards and I'm satisfied with my preference of the 6.5 Grendel.  The added benifit of less powder lets me stretch my shooting dollar a little further.  With the 6.5 Grendel I can shoot as much as I like and don't suffer from fatique of shooting heavier recoiling cartridges.

Will 6.5 shoot in an 18" bbl?  Sure!  I have no doubt whatsoever it's a great seller.

However - if you're buying a round based on one set of data, imagining that it will do what you want regardless of barrel length you're mistaken.  Will it work?  Sure.  Will it kill?  Sure.  The energy numbers, though just aren't there.  Velocity -does- matter.

It's so strange to me - shooters want more energy so they change to a non-standard caliber.  Then they reckon that big long barrel is a waste since "it will shoot anyway".  Result?  Dump a good chunk of that energy gained from the caliber switch.

??

Believe whatever threads you want - chronographs and math don't lie.

Chronographs and math don't lie, but they don't tell the whole story, either.

Basing your caliber decisions on energy sort of flies in the face of a ton of terminal ballistics research that says energy is not the primary mechanism by which bullets wound or kill. As a hunter, there are many other factors to consider as well.

Of course, no one is saying 6.5 Grendel is the be-all and end-all of hunting cartridges, but it does cover a pretty large sweet spot in terms of North American game animals and is pretty much all most hunters will need - even out of a barrel shorter than 24 inches.

Well OP whatever you believe regarding calibers:
vs 6.5

308 ammo availability will always be better.  If a store carries 5 rifle calibers' ammo 308 will almost certainly be one of them.
308 ammo can be had cheaply in loaded plinking ammo.
308 bullet selection will always be better.
308 energy will always be better (308 pistols and SBRs aside)

Downrange ballistics are another matter entirely.  However I'd be the first to tell you both should hit to 250 yards without fiddling with your scope at all.  Beyond that both will require adjustments and you will need to know both range and your drop pretty accurately.

If only WDM Bell would have had a .308 when he killed over 1100 elephants in the white gold era in Africa, 300 of which were slain with the 6.5x54 Mannlicher.

You have to ask yourself why people like me, who have spent decades behind the trigger of a .308, dumped it like a bad habit in favor of 6.5 Grendel.

Impact speed on target is more important if we're talking about getting expansion, along with sectional density.  On numerous hunts now, post mortem analysis of various species of game shows imperceptible difference between wound channels from 6.5 Grendel and .308 Win.

One of them you can train with all day long with no recoil fatigue at all, as can your wife and kids, without needing a muzzle brake.

The other has substantially more muzzle blast, more than twice the recoil, and not all of the factory ammunition was designed with gas gun operation in mind.  Wind drift is also more with .308 Win., and working pressure is ~8,000psi higher or more.  Every time I pull the trigger on a .308, I am reminded of what a great decision it was to get out of that cartridge.

24" barrel needed for 6.5 Grendel?  I still have yet to own one and probably never will, yet I have 4 Grendels with more in the works.  Hornady's 8th Edition lists 14.5" barrel data, their 9th Edition lists 18", Western Powders lists 20", and the others 24".

Projectile weight range is from 85gr to 160gr, but the most popular selection is 85-130gr, with 123gr being the dominant weight.  You have better BCs than a 175gr SMK in the .308 when shooting 123gr in 6.5 Grendel, with a much tighter twist rate, so effective range and hit probability are noticeably better in practice.  I see this all the time in my courses.

We included everything from 10.5" to 24" data in Volume II of the 6.5 Grendel Reloading Handbooks.

Volume I includes data for the various AR15 gas system and barrel lengths, a well as a velocity estimator if you know the v0 of one and are looking for a close estimate of another.




In the end, .308 is a 20th Century cartridge born out of the inability of the Army Ordnance Corps to learn from the lessons of both The Great War and World War II.  The 6.5 Grendel is a 21st Century cartridge that packs late 19th century performance into a case that fits inside the ubiquitous AR15.  I think you will enjoy the AR15/6.5 Grendel far more than you ever could the .308/AR10.

I don't see where saying one cartridge in 6.5 means all 6.5 cartridges must be good.  You might as well stack 30 carbine, 300 Savage, 30-30 and 308 under the 30-06 or 300 Ultra Mag banners...  For that matter 8mm should be the best around since only a few million of those were made and used (and still used) to kill every living thing on the planet...

Don't get me wrong 6.5 offers a lot.  I would like to see load data for a 160gr bullet loaded in 6.5 Grendel (that feeds in an AR-15 - NOT a bolt-gun-only load), though.  308 tosses a pill that weight at 2700+ fps in a 20".

One of the slowest of all the late 19th/early 20th Century cartridges, the 6.5x54 Mannlicher, is basically duplicated by the 6.5 Grendel, using a much smaller case.

Of course you can punish yourself to get the same results with excessive recoil, but hit probability suffers with more recoil.

If you look at the Scandinavian moose hunting surveys where they gathered data on over 14,000 moose kills, for example, the most efficient calibers were 6.5mm and 7mm when measuring animal travel distance from the shot.

The .45 bores had the least travel distance, but recoil is substantial.

The .30 calibers had the longest travel distances.  The 6.5 and 7mm samples had noticeably less travel distance than the .30 calibers (mostly .308, .30-06, and .300 Win Mag).  The terminal performance isn't really noticeably different, but recoil and hit probability are.

So if a cartridge has over a 100 year proven history of killing moose to the tune of over millions of samples (they average over 200k moose per year between Finland, Sweden, and Norway), what sense does it make to choose a caliber with reduced hit probability due to recoil.

That's why I recommend 6.5mm any day over .30 bores.

Also, if you really wanted to duplicate the 6.5x54 M-S 160gr Round Nose load in the 6.5 Grendel, it has been done already.

Most people using that bullet are doing it subsonic though.

6.5 grendel 123 amax SD .252
Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE100200300400500
2580/18182410/15862247/13792090/11931940/10281796/881

308

150sst SD .226
Velocity (fps) / Energy (ft-lbs)
MUZZLE100200300400500
3000/29972772/25582555/21732348/18362151/15401963/1282
Trajectory (inches)
MUZZLE100200300400500
-1.501.500.00-6.90-20.00-40.70

165 sst .248
Velocity (fps) / Energy (ft-lbs)
MUZZLE100200300400500
2840/29552635/25442439/21802252/18582079/15741902/1325
Trajectory (inches)
MUZZLE100200300400500
-1.501.800.00-7.60-22.10-44.70

AT 500 yards the 308 still has 200 fps advantage and nearly 500 fl lbs of energy 165 sst has very similar SD to the 123 6.5 grendel bullets Also has the advantage of starting at .308 vs .264
All velocity using 24" barrel.  Please tell me the magical properties that make the 6.5 grendel hit as hard as a 308 despite giving up momentum, fps, bullet diameter and loads of energy?
also hornady hits for above 6.5 grendel 800
hornady hits for 308 165 sst   1162.
By any measurable metric the 308 kicks the snot out of the 6.5 grendel out to 500 yards, if you need to shoot live animals out past 500 then you need to find something different from both of them or learn how to hunt.  Doesn't mean the 308 is better, grendel (gun) is cheaper, lighter and has less recoil.  It also will kill deer just as dead, 308 is more than is needed for deer.

And .300WM beats .308, and .338LM beats .300WM and on and on.

The point is, Grendel offers enough performance for many hunters in a compact, lightweight package. You always "give up" something when you move up or down in caliber or cartridge capacity. If you want .300WM performance, you "give up" soft recoil, portability, and light weight (and no, muzzle brakes are not the answer - had a .300WM with 26" bbl and brake and it was an obnoxious bastard).

Not every tradeoff is about MV and energy.

Never said it was LRRPF52 has posted multiple times that the 6.5 grendel is equal to the 308 in performance.  I was simply saying NO ITS NOT AND ITS NOT CLOSE.  As I said in my post this FACT doesn't mean the 308 is better than the 6.5 grendel, I mentioned the 6.5 will be lighter, have less recoil and kill deer just as well, because the 308 is really more than is needed for a 150 lb whitetail at 100 yards.  What magical power of the 6.5 will make a bullet with similar SD, much less energy and momentum, and that starts as a smaller diameter equal the 308?

Post mortem analyses of wound channels can't tell the difference between .308 and 6.5 Grendel.

Travel distance from the shot is the same or less with 6.5mm, not because of the caliber, but because shot placement is easier with 6.5mm.

The point is, why beat yourself up for less performance when you don't have to, just because there were .30 caliber nazi's at Army Ordnance in the 1950s who refused to learn from the past?

Good luck humping and holding a 24" .308 AR steady on a hunt.  I personally never saw those speeds with 24" and 22" .308 ARs with 150gr, even with over max hot loads.

I was maxing out at 2820fps.  I just checked Hornady's data, and unless you're shooting Superformance loads (good luck with that in a gasser), they list 2800fps as max with 150-155gr from a 22" 1-12" twist.  Their service rifle data lists 2700fps as max with 155gr AMAX.

I'm not going hunting with those barrel lengths unless I'm doing a purposeful long-range hunt with .260 Remington.

Where you really want to look for practical hunting is the 16-20" barrels and look at wind drift, as well as impact velocities and the expansion thresholds for the bullets you are using.

The 129gr 6.5mm Accubond Long Range will hit faster at distance than the 150gr .308, after 400yds, and has a longer Point Blank Range.

You lose point blank range quickly with .308 because of low BC, no matter what bullet you use.  Spit a light bullet with low BC fast?  Still drifts like a drunk in an alley.  Spit a high BC but heavy bullet slow, you have less drift, but rainbow trajectory.

Within 200yds, hit probability is high with both of them, and both have more than enough penetration and expansion to anchor the game.  You just get beat up and damage your ears more, while humping a heavier stick that is harder to make the shot with using the .308, which will average several pounds more than the AR15.

Now start looking at your 300yd and 400yd shots.  This is where you see the wind drift of the .308 really screw you over.  All that energy does no good if you gut-shoot the animal, or clip their throat, leg, etc.  Now you get to trudge through the woods, or in my case, the mountains, looking for your lost and wounded game that is running like a bat out of Hades into the hinterland, often never to be found.

Wind reading errors are very unforgiving with .308 Winchester.  It just sucks in the wind unless you use a better BC bullet, like a 178gr AMAX, which is excellent for killing BTW.

The only cartridges that make sense in the GII if you want to be competitive with the AR15 6.5 Grendel are:

7mm-08
.260 Remington
6.5 Creedmoor

These all have excellent BCs, excellent flat trajectory available with the lighter bullets (that still have beautiful BCs), less recoil than the .308, and better terminal performance that compares well with .30-06 Springlfield and .270 Winchester.

You will still have a slightly heavier gun, and it needs to be built by someone that knows how to manage and place the port pressure of these higher capacity cases that use slower burning powders.  7mm-08 is the easiest to just leave with a RLGS and shoot 139gr, 140gr, 154gr and not change much.  The 6.5s are more temperamental when it comes to porting.

For me, it's just easier to go 6.5 Grendel and have a little fire stick that feels like a toy in weight, has very low recoil, with higher hit probability into the vitals.

I'll continue to take my 7lb 12oz 6.5 Grendel with optics, and have a higher chances of hitting in the vitals than .308 any day of the week.  I sold all my .308 ARs and never looked back.

I agree with this post. If your going to go G II get a different caliber with better trajectories than .308.

 

I'm going to be building a 6.5 creedmor gasser soon.

AGAIN LOOK AT THE BOLDED PART.  THE PERFORMANCE WON'T BE THE SAME AND IT CERTAINLY WON'T BE LESS.  I POSTED HARD NUMBERS FROM HORNADY'S WEBSITE INCLUDED HORNADY HITS.  THE 6.5 GRENDEL IS NOT CLOSE TO THE 308.  YOUR A 6.5 HOMER WE GET IT AND ITS A GREAT CARTRIDGE AS I SAID IN MY ORIGINAL POST IT MAY EVEN BE BETTER THAN THE 308 FOR MANY USES.  BUT THE PERFORMANCE EDGE GOES TO THE 308 AND BY A GOOD MARGIN.  THERE IS NO WAY A BULLET WITH LARGER DIAMETER AND 500 FT LBS OF ENERGY EQUAL SD IS GOING TO DO LESS OR EQUAL DAMAGE UNLESS YOU ARE USING A FAST EXPANDER VS A CONTROLED EXPANSION BULLET. THE 308 165 IS HITTING AT A FASTER SPEED AT 500 YARDS THAN THE 6.5 GRENDEL ITS GOT BASICALLY THE SAME SD IS STARTING OUT WIDER AND HAS 500 FT LBS ON THE GRENDEL.  I don't have a dog in the fight.  I don't own a 308 semi, we can't hunt with semi auto's in PA, I do have a savage 99 in 308 but I am in no means a homer for the 308.  You don't need to lie the the OP to get him to choose the cartridge you have a hard on for.  The cartridge can stand on it's own merits, like I said its a great cartridge for a ar15, but its not near 308 performance.  I am done arguing about it I don't care just wanted the OP to know the truth.

The .308 and .260 are both going to reach out there with more authority.

WM Bell killed more elephants with a 7mm Mauser than anything else.
He dissected the skull and found just where to shoot them in the head.
Using this reference is silly as he could have used almost any caliber.
The .275 Rigby was said to be his favorite.
"This made it popular in Africa, where it was used on animals up to and including elephants, for which it was particularly favoured by noted ivory hunter W.D.M. "Karamojo" Bell, who shot about 800 African Elephants with 1893 pattern 7×57mm military ball ammunition using Rigby Mauser 98 rifles, when most ivory hunters were using larger-caliber rifles.[15] Bell selected the cartridge for moderate recoil, and used 11.2-gram (172.8 gr) long round-nosed military full metal jacket bullets for reliable penetration. Bell sectioned an elephant skull to determine the size and location of the brain, and used careful aim to ensure bullet placement in the brain.
He also used a Mannlicher–Schoenauer 6.5×54mm carbine, a Lee–Enfield sporting rifle in .303 British and rifles chambered in .318 Westley Richards."
Perhaps one of these would be a good GII caliber.

If you want to run a 6.5 a Creedmore or .260 Rem is the way to go.

I would like to see proof that a 6.5G and a .308 have the same would channel.
That would be interesting indeed.

I would love to see the load data and pressure data on those .308 loads. Those velocities are a match for a hot loaded 30-06 in a bolt gun, but not .308.

they won't if they use bullets with similar expansion characteristics.  Sure a 123 Amax may make as wide a wound as a 150 grain tsx.  But with similar bullets the wound channel will be wider with the 308 because the bullet is impacting at a faster speed and is already wider.  I don't care what the bullet's doing at 1k yards because you shouldn't be shooting at live animals past maybe 500 with either one of these cartridges.

Exactly.
I would reel the yardage back more than that but thats just me.

You might want to go read the COC before you post anymore.

You listed 3000fps for a .308 with a 150gr.  Good luck with that.

I've been reloading for .308 for many years, well over a decade at least, mostly in gas guns.

A 129gr ABLR from an 18" 6.5 Grendel has higher impact speed on target at 400yds than a 150gr hunting bullet or AMAX even from an 18" .308 at 400yds.

Both have more than sufficient energy to penetrate through and through.  One has way more wind drift and over twice the recoil, from a heavier gun.

If you have more energy that misses the vital zone, what does that get you? A long walk through the woods/mountains while an animal suffers.

Rather than posting yet another picture of your rifle.
Why not post references that show something to back up your statements?
Show that the G has more retained energy and a bigger wound channel both permanent and temporary than a .308. @ 400 yards.
Show it at sea level as well as 5000 ft where you live.
Comparing the exact same composition projectile.  
Show it at 400 which is even then a stretch on medium bodied animals and humane hunting practices.

To say people cant hit anything at 400 yards with a .308 is a more than ludicrous as well.
Given the number of 1000+ yard sniper kills to its credit.

I do not consider it "way more wind drift" when talking a couple inches vs more hitting power.

And just like that another thread goes to shit. Oh well.

Do you know what SD means and how it's calculated?

What kind of velocity data are you using to determine that the .308Win is superior to the 6.5G at 500yds?

Thanks-

Looks like some hardcore 308 love in here

you can use a semi to pull your boat, or go with a ford 150.  Guess it depends on the boat.

Wow, I got back from work and discovered that this thread blew up faster than a 6.5g bolt with a hot handload. Lots of good information here. One note is that I'm not planning on hunting anything at longer than 300 yards. If I want hunt at a longer range, I'll use my 30-06 Tikka. The 308 beats the 6.5g for power at these ranges. My brother's 7mm wby mag beats both of them for long range hunting. It's not really about power. It's about having a gun that can ethically hunt deer at closer ranges but is also fun for target shooting.


I'd really like to see the safe SAAMI spec velocities on the 6.5g from a 20in barrel. Does it compare with a 30-30? .250 savage?

How is the reliability on these guns. I've heard of complaints with both the GII and the grendel?

A lot of people reccomended an ar in .260. One issue with this is that the .260's seem to have more difficulties with the gas system, requiring hand loading.

OMFG
I'm rolling..........
Somebody give this guy a 100 year old Scotch and a Cuban........

Its hornady superformance ammo right from their website.  Numerous posters have said they have no problem running superformance with adjustable gas.

I pulled the specs right from hornady's website.  its superformance ammo.  I have reloaded for a 22" bolt gun and 2900 is not hard to get with wise powder choices.  2800 is also very do able for the 165 grain weight class.  Nosler's ammo is almost equal to the superformance ammo as well with 150's running around 3k and 165's at 2800 fps those are out of a 24" barrel but I listed the grendel specs from hornady's website with a 24" barrel as well, I could have used the 16" but wanted the top loads available for both.  Hornady's ammo for the 6.5 is hotter than alexander arms correct?

I am not arguing the choice of the 6.5 over the 308 I am however pointing out that you are saying the 6.5 gives you more performance than the 308 with less recoil.  Which I posted hard numbers that shows that is not true.  
Here is more specs
Federal 308 msr 1780 fps at 500 yards with 1058 ft lbs those numbers are out of a shorter barrel but federal doesn't list 16" or 20"
hornady 6.5 grendel
123 sst  is 1796 at 500 with 881 ft lbs with a 24" barrel
and      1612 with a 16" barrel 709 ft lbs.
Of course those numbers favor the 308 more and more as the distance is shorter.  consider most won't shoot over 200 yards very often the 308 spanks the grendel in performance which is what I am pointing out.  Had you said the 6.5 grendel gives you enough performance with less recoil I would agree with you but you keep saying the grendel is superior performance wise and that simply isn't true.

using hornady superformance or federal msr 150 grain vs hornady 6.5 grendel.  Both with equal length barrels are hitting at 500 yards faster than the grendel while having more weight.  I wanted to point out that the SD of the 165 30 caliber and the 123 6.5 are basically equal so all things being equal they will penetrate the same(they won't the 308 will have more momentum)

So you don't have a clue what it actually runs.

And I've had three different calibers of Superformance blow primers so it isn't running normal pressure. I had a 308 Superformance blow a primer chunk into a he firing pin channel of my SR 762 and lock it up. I'd stay away from that shit.

Ummm.....bolt guns don't apply in this thread.



 

No mistake - I am a huge fan of 'medium-power' cartridges and generally think people are over-gunned.  To my dismay I see shooters here buy 300 Mags for deer (our deer are a bit bigger than a good sized dog).  Grendel for deer here would be fine; no question of it.  6.8 SPC is a local favorite for both deer and hogs.  All that said I maintain that these rounds are the beginning of ethical hunting for deer / hogs.  

One of these calibers offers 1800 ft lbs ME - on a fairly hot load and energy-favorable configuration in the rifle
The other offers 2500 ft lbs with a relatively moderate load, in a somewhat shorter barrel and probably still slightly larger rifle overall.  Really hot loads in long barrels can push quite a bit more.  Hornady's "Superformance" states 2955 FPE (165gr SST).

Even referencing the lower-power rifle / load combinations 700 FPE gives you a lot of options.  It all boils down to choice.  Recoil will probably be less in 6.5 even though the rifle is also very likely to be lighter - both are good things.

I did look up that 6.5x54 load and found what I expected.  That velocity and high SD, tough-constructed bullet is a great combination.

6.5 CREEDMOOR  IMO has 308 by the pants and TBH it isn't even close.  Best of both worlds - though personally I like 7mm-08...

Superformance is not meant to be used in gas guns.  I was getting high pressure signs at 2,600 fps with it from my 6BRX.  Varget would get me to over 3,000fps with no pressure signs.  And accuracy with the superformance was abysmal.

Interesting - I have never heard that.

I have also never seen pressure signs with it.  Are you aware of any documentation or specific information from the manufacturer on this?  If it's just observation, no worries and appreciated but I wouldn't mind knowing.

<ALSO>

Hodgdon publishes data pretty darn close to Superformance velocities using CFE-223 at 150gr and 165gr.  But now I supposed there's probably something horribly wrong with that powder, too?  If so does it also apply to Varget - about 50 FPS behind?

They claim it's best in 20"+ barrels.  I was getting consistent failures to extract out of a 22" barrel with adjustable gas.  Anything loaded hotter than 2,600fps would not extract.

http://m.hornady.com/ammunition/superformance-in-gas-operated-firearms

The below quote I just copied off one of my boxes of .308 Win Superformance. No mention of autos anywhere, good or bad. But I agree its not good for autos from my experience. Noticeably heavier recoil was the first thing I noticed. Then looking at the brass and seeing the melted primers, pin cratering and case head flow into the extractor holes. 44 years of reloading for .308 Win says plainly to me that Superformance is HOT stuff regardless what's printed on the box.

Plus I've had nothing but crappy accuracy with Superformance 150gr and 168gr SST like 3" to 4" groups from my G2 Hunter which will shoot MOA and under.

I think the point that several people are trying to make is that the .308 offers a muzzle energy advantage that isn't really all that relevant in most cases to performance on deer, but it does so at a noticeable cost in terms of weight, recoil, and external ballistics.

Heck, if it's PA deer we're talking about - and in PA - I'd have no qualms about .300blk supersonic, 7.62x39, 30-30, etc.   Any of the rounds OP is talking about will get the job done; the question is probably which ones satisfy his range toy requirements.   Nothing wrong with wanting a neat rifle.

Everyone has their preferences.  For a range toy I'd still go with the caliber that's cheaper to shoot.  If you reload it's a wash - 6.5 I will admit is NOT at all hard to find or load for.  The rifle will all things being equal be a bit more.  Mags will be a bit more.  Brass will cost a bit more.  

I built my 308 to bang the gong at 300-800 every pull of the trigger and take cleanly every critter on the continent save the great bears.  If OP wants to stick with "Deer and down + range" then 6.5 DOES work.

Energy gives you options and at my size another 2-3lbs of rifle (and it isn't that much) I don't even notice.  However not everyone is built like a fire hydrant.  

The part that gets me is saying one = the other in capability.  The #s and experiences just don't agree with that.  It is almost like saying 30-06 will do anything 338 WM will do.  Well - as with all things the answer is 'well-sorta'.  Both are fine cartridges.  Both will take anything on this continent.  Neither is a big 5 cartridge but I bet they've both been used on every critter that walks the earth.  Still - saying they have the same capabilities is just inaccurate at best.

As with all things YMMV...

There's no way you're getting those velocities in a .308 gas rifle without blowing primers.

This is pretty much it. This is the first gun I'll be buying that I don't truly 'need'.

2 pages about rifles you can't hunt Deer with in PA anyway....

I guess you could build a Troy pump upper....

You do know that semi auto's are a no go in PA correct.  I just wanted to bring that up, though hopefully that will change in the near future.  Agree that any of the calibers listed above will work for PA deer hunting, most shots are in close and a good sized deer will be 150 lbs(although a big mature buck can be in the 200 lbs range)