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Posted: 11/4/2008 5:17:46 AM EDT
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Hiya Folks,
Well it looks like I'm building a 6.8 for myself. I really hadn't planned on doing it but broke down and ordered a barrel from Cardinal Armory before they're all gone. I will be slowly getting all the parts together for this. To date, I have the barrel, handguards, front site, and flash hider. I pretty much know what I want for the upper and lower receivers (going with Mega probably, or perhaps Anvil). Where I'm getting a little hung up is on the BCG. I'm having a hard time finding any in stock at most of the suspect places and even then, I'm not sure what I want. I'm debating between two options really and was hoping to get some insight from any users out there. The first option is to go with the CMT Bolt/Carrier. It's cheaper pricewise and I really haven't found anything that suggests it's not a good setup. The other option is to go with a Young's NM carrier and LMT bolt....all chromed/diamond black. This sounds like the best setup but it $$$. So for you 6.8'ers out there, have you had any issues with the CMT setup or have a particular reason you recommend the Young's/LMT setup? Sorry for being so long winded! Cheers, cc |
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Bought it direct from here:
Young Mfg. Also, just for info, I went with a Spikes upper and lower on the build and will be using a 10.5" Noveske barrel. |
| i got the full BCG and will swap out the bolt to the 6.8 LMT bolt. You probably won't find the 'perfect' fully assembled 6.8 bolt as generally the fully assembled 6.8 bolts are the inexpensive CMT Stag variants. If you want a nice bcg, either build it or buy a nice 5.56 BCG and swap the bolt. |
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*dennys has 6.8 bolts and complete assemblies
*ranier arms does too *white oak armamnet does *jtac supply does too... to name a few... I went with a white oak barrel with matching bolt and carrier group... it is a cmt... I then sent it away to a 6.8 master to be properly set up... including a perma pin and an upgrade similar to the e.g.r.e.s.s...... I did not have a titanuim firing pin installed as it was not recommended for a combat rifle due to its inevitable ability to chip and pierce primers..... its not necessarily the bolt manufacturer but how the bolt is assembled and corrected perfectly for the 6.8 round.... any 6.8 bolt you buy should probably be upgraded for optimum performance.... I opted for a sun devil billet upper instead of a production forging... I coupled it with a sun devil billet lower and added anti walk pins to the trigget and hammer..... make sure you get a .308 size flash hider |
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its not necessarily the bolt manufacturer but how the bolt is assembled and corrected perfectly for the 6.8 round.... any 6.8 bolt you buy should probably be upgraded for optimum performance.... Thanks for the info. Do you believe the LMT bolt needs to undergo this upgraded work as well or is it pretty much ready to go out of the box? Cheers, cc |
| In truth, there are way more CMT/Stag 6.8 BCGs being used than probably anything else, and they all work flawlessly. I really don't think you'll get a bad setup. The 'National Match' is considered by many to be overkill if your not competing in precision and the chrome is not necessary but an advantage when cleaning; I went with the NM because I'm an anal freak. Get a Young chrome bolt carrier (non-National Match) and put in an LMT 6.8 enhanced bolt and you'll be more than ready to go. |
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I have to agree with many of the comments here. Remember that if you shoot hot ammo, like SSA combat loads, the forces on your bolt will be greater. Some of these rounds are generating 58-60,000 PSI and while these guns generally can handle that, you will almost certainly see earlier parts breakeage, like extractors if you use the "standard" CMT bolt.
I personally went with the YNM chromed carrier and LMT enhanced bolt and this bolt has the lobster claw extractor and upgraded springs. It also is much easier to clean and has an inherent lubricity that is better than a phosphated bolt. I'm maxing out my rigs with a suppressor and hot ammo, so I want every durablity edge I can get. We have known for many years that the small bolt lugs of the AR-15 are a weak link. I want every edge I can get for my rifles, especially at a time when we are all afraid that we will not always be able to depend upon easily attained and inexpensive replacement parts. I am happy enough with the YNM carrier and LMT bolt that I will be buying another for my SBR. |
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I bought two LMT BCGs from Rainier and swapped out the bolts.
For my 16" hunting 6.8 I'm using the carrier as it came stock and swapped in a CMT bolt. For my 18" SPR 6.8 I am having the carrier Ion Bonded and am using the LMT chromed/enhanced bolt. The 5.56 MPI bolts that came with the BCGs will be spares for my M4gery and SOPMOD. MSTN has LMT carriers by themselves and can get the LMT 6.8 bolts. You'd need to add the small parts. |
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Guys,
Im in teh process of possibly building a 6.8 16". Can anyone tell me why NOT to buy a Model 1 Sales 1:9.5 barrel? Also, everyone seems happy with Cardinal barrels do I have to worry about shooting remington/TAP/ect ammo but probably NOT the SSA Combat Loads in either a Cardinal or Model 1 barrel? Thanks and sorry for the ignorance!! |
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I highly recommend floating over to 68forums.com as there is some great information there. As for the Cardinal barrels, well if you're set on a 16" you're out of luck as he's done selling them. Last I saw, he only had 18" barrels left. And there's been a ton of discussion on what the proper twist rate is. Generally from what I've gathered, a 1:11 twist is the ideal twist. Personally I'd go look at other barrel mfg's for the 1:11 twist rate vs. the Model 1 sales version. If you do find a Cardinal barrel, I believe they will all shoot non combat loads with no problems. And in saying that, many of his barrels will also handle the combat loads although he isn't guaranteeing it given his chrome issues.
Cheers, cc |
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Guys, Im in teh process of possibly building a 6.8 16". Can anyone tell me why NOT to buy a Model 1 Sales 1:9.5 barrel? Also, everyone seems happy with Cardinal barrels do I have to worry about shooting remington/TAP/ect ammo but probably NOT the SSA Combat Loads in either a Cardinal or Model 1 barrel? Thanks and sorry for the ignorance!! Because a SAAMI chambered 1 in 9.5" twist is the highest pressure environment through which you can shoot any 6.8 SPC loads. If you can think of ANY single advantage a twist rate of 1 in 9.5" gives you, then let us all know. With the "varmint" weight for caliber bullets used by the 6.8 SPC, it is 100% illogical to use the fastest possible twist rates which are designed to stabilize the longest (usually thus the heaviest) bullets. You should also know that stability is determined by the density of the bullet and the length, NOT the weight. People using 1 in 10" are basing that upon .270 Winchester barrel design, and those using 1 in 9.5 obviously know very, very little about the cartridge and its properties. If 1 in 11 or 12" isn't the optimum, then why would Noveske, Stag and others now change their rifle designs to this spec as they move forward? They know what we know, and my hat is off to them. I have seen the 1 in 12" twist stabilize the 110 grain barnes TTSX's (~1.2" long) so all this talk about the "heavier bullets not being stable in 12 twist" is just BS spewed by people that have never fired a 6.8 SPC. Get a 1 in 11" or 1 in 12" period. The only 1 in 10's I've seen that reliably shoot the combat loads and hot handloads are the LWRC M6A2 and M6A3 with the new rifling geometry and nitrocarburized cold hammer forged barrels. Some RRA's without chrome are handling these loads, but all mass-produced barrels show some variation in bore diameter and thus are going to vary. RRA is also considering a 1 in 11", and now that Stag just came out with the Model 6L (?) hunter in 4 groove 11 twist, (WAY TO GO STAG!!  ) they have to do so.
The LWRC's are going to cost you as much as three uppers from Cardinal or AR Performance. Since Cardinal is out of business, you should now look to AR Performance, and if you think the risk of waiting is worth it, then Noveske, LW and Titan Arms (making an upgraded version of the Cardinal barrels) should have their bad-ass barrels out in another month. HTH 
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one thing i'm not sure some people realize is not everyone out there is on a trip to where we have to shoot the hottest hottest loads ever possibly made.... i don't handload, don't care about ordering the 'special' SSA combats, I just want a good overall round to shoot. Just because I have Nitrous here at the house for my race bike doesn't mean I have to run it in every vehicle I own.
I like Hornady and generally shoot a lot of TAP, which is what I'll be shooting with the 6.8SPC. I don't go to the range for thousands and thousands per visit either. With that, the 1:10 Noveske that I just recently ordered is more than sufficient for my needs, I can shoot whatever I want out of it and I'm confident it'll provide everything I so desire. So, when people are giving advice, they have to consider other people's needs, not their own. I am happy to see the industry trying to improve themselves, and if 1:11 is truly superior then it's good to see them making the transition. I just wish Noveske would've told me about it when I ordered so I could've swindled them into a discount for the 'old' technology.... :) |
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one thing i'm not sure some people realize is not everyone out there is on a trip to where we have to shoot the hottest hottest loads ever possibly made.... i don't handload, don't care about ordering the 'special' SSA combats, I just want a good overall round to shoot. Just because I have Nitrous here at the house for my race bike doesn't mean I have to run it in every vehicle I own. I like Hornady and generally shoot a lot of TAP, which is what I'll be shooting with the 6.8SPC. I don't go to the range for thousands and thousands per visit either. With that, the 1:10 Noveske that I just recently ordered is more than sufficient for my needs, I can shoot whatever I want out of it and I'm confident it'll provide everything I so desire. So, when people are giving advice, they have to consider other people's needs, not their own. I am happy to see the industry trying to improve themselves, and if 1:11 is truly superior then it's good to see them making the transition. I just wish Noveske would've told me about it when I ordered so I could've swindled them into a discount for the 'old' technology.... :) Too bad you didn't wait until Noveske changed their stuff over to the 1:12" twist they're about to unleash! A 1:10" twist barrel with the proper chamber is probably going to be fine. A 1:11" twist barrel with the proper chamber will definitely be fine. Saying that someone new to the 6.8 game should get a 1:11" or 1:12" is actually the safest thing to do. It makes it near "idiot" proof! 
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Too bad you didn't wait until Noveske changed their stuff over to the 1:12" twist they're about to unleash! A 1:10" twist barrel with the proper chamber is probably going to be fine. A 1:11" twist barrel with the proper chamber will definitely be fine. Saying that someone new to the 6.8 game should get a 1:11" or 1:12" is actually the safest thing to do. It makes it near "idiot" proof!
I definitely agree with getting the best possible updated stuff but the needs of a person have to be considered and while I wouldn't complain about having the newer 1:11 stuff, I'll be perfectly fine with 1:10 and I'm sure the Noveske barrel I purchased will be 10x more accurate than I ever could be with it and will surpass the needs I'll be asking of it. |
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Too bad you didn't wait until Noveske changed their stuff over to the 1:12" twist they're about to unleash! A 1:10" twist barrel with the proper chamber is probably going to be fine. A 1:11" twist barrel with the proper chamber will definitely be fine. Saying that someone new to the 6.8 game should get a 1:11" or 1:12" is actually the safest thing to do. It makes it near "idiot" proof!
I definitely agree with getting the best possible updated stuff but the needs of a person have to be considered and while I wouldn't complain about having the newer 1:11 stuff, I'll be perfectly fine with 1:10 and I'm sure the Noveske barrel I purchased will be 10x more accurate than I ever could be with it and will surpass the needs I'll be asking of it. Noveske makes the best mass produced barrels, bar none. I'm pretty sure we can count that as fact due to what we know they can accomplish! I may have to get rid of a few 556 uppers and replace them with the likes of Noveske 6.8. I'll keep a general duty 556 and a match version, and the rest will go to 6.8 and .458 SOCOM as my primary hunting and defense rounds. |
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one thing i'm not sure some people realize is not everyone out there is on a trip to where we have to shoot the hottest hottest loads ever possibly made.... i don't handload, don't care about ordering the 'special' SSA combats, I just want a good overall round to shoot. Just because I have Nitrous here at the house for my race bike doesn't mean I have to run it in every vehicle I own. I like Hornady and generally shoot a lot of TAP, which is what I'll be shooting with the 6.8SPC. I don't go to the range for thousands and thousands per visit either. With that, the 1:10 Noveske that I just recently ordered is more than sufficient for my needs, I can shoot whatever I want out of it and I'm confident it'll provide everything I so desire. So, when people are giving advice, they have to consider other people's needs, not their own. I am happy to see the industry trying to improve themselves, and if 1:11 is truly superior then it's good to see them making the transition. I just wish Noveske would've told me about it when I ordered so I could've swindled them into a discount for the 'old' technology.... :) Strange that you make the claim "the needs of a person have to be considered..." yet you confuse this with my direct answer to the question posed. If you call my testing and mission to inform manufacturers about the limitations of the original SAAMI specs, (which bear little resemblance to the original guns designed by Murray and Holland) a "trip" then you must be smoking something really funky. My needs vary from your needs. I need to be able to shoot ALL AVAILABLE ammo in my rifle not just one certain bullet or watered down load, or else that weapon has limited usefulness. I do not always, and don't expect anyone else, to "...shoot the hottest, hottest loads ever possibly made...." 
I am delighted that you are happy with your Noveske 1 in 10" rifle. I wonder if you could explain their "trip" since they decided to go with a DMR-style chamber and 1 in 12" twist?? 
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I am delighted that you are happy with your Noveske 1 in 10" rifle. I wonder if you could explain their "trip" since they decided to go with a DMR-style chamber and 1 in 12" twist?? No need to get offended, that wasn't directed specifically and only at you; I'm not questioning your advice, testing or intelligence just saying that not all of us are going to be running the super potent hi-output combat loads. They're not available around here, so unless I mail order them, I won't have any around me and I'm not interested in them. Just relaying that this person may not either and people tend to over think and over dramatize choices. I'm sure there's a reason, as you suggested, for going to the 1:11, in fact I said I'm happy to see the industry following customer desiers and improve themselves, but does that now mean the 1:10 is just so inferior that no one could ever be happy with it? Same thing with the 1:7 to 1:9 5.56 debate, there are loads of people running 1:9 and love them, does that mean it's better or worse than the 1:7, no, it's just a different setup that will accommodate certain people differently than others. |
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I am delighted that you are happy with your Noveske 1 in 10" rifle. I wonder if you could explain their "trip" since they decided to go with a DMR-style chamber and 1 in 12" twist?? No need to get offended, that wasn't directed specifically and only at you; I'm not questioning your advice, testing or intelligence just saying that not all of us are going to be running the super potent hi-output combat loads. They're not available around here, so unless I mail order them, I won't have any around me and I'm not interested in them. Just relaying that this person may not either and people tend to over think and over dramatize choices. I'm sure there's a reason, as you suggested, for going to the 1:11, in fact I said I'm happy to see the industry following customer desiers and improve themselves, but does that now mean the 1:10 is just so inferior that no one could ever be happy with it? Same thing with the 1:7 to 1:9 5.56 debate, there are loads of people running 1:9 and love them, does that mean it's better or worse than the 1:7, no, it's just a different setup that will accommodate certain people differently than others. I'm not offended, just saying that you have missed the point completely. When the .223 became the 5.56 X 45 mm, what happened to the chamber? Yes, that's right, it became the 5.56 chamber, and it is no longer OK to shoot hotter 5.56 loads in a .223 chamber. So, with the 6.8 SPC, when the first guns to hit the market used the SAAMI chamber, and 1-10 twist, it was patently obvious that the makers of these rifles didn't realize they were limiting their customers to only certain rounds. In fact, LMT told one Poster here that "we only recommend ONE brand and type of ammo in our rifles..." What happened with the 1 in 9.5 and 10 twists is that people mistakenly believed that the .270 Winchester would work in them and so should the 6.8. WRONG. If you hunted with your rifle, you might want to shoot more than just Hornady TAP. That ammo is essentially useless to me, and you said that the needs of each person need to be considered. Well, your needs are very limited, and mine are widely varied. So, don't presume that the person asking that question would want to be limited to your idea of "adequate." That is exactly what almost killed the 6.8 SPC. People like Lothar Walther, Noveske, AR Performance, Stag, RRA, Charles Daly defense, and others now clearly recognize that the market wants a versatile 6.8 barrel. The 11 and 12 twists will shoot any bullet made, so these make the barrel more versatile. When you are limited in the bullet selection of 6.8 (and .277''s have traditionally been quite lame), then it just made things that much worse. To limit the user to the 10 twist has NO ADVANTAGE, and can only render disadvantages. If you are going to try to claim accuracy is better in the 10 twist, look at the performance of the MSTN upper in the upper evaluation done last year. It was 11 twist, and nothing could touch it. Does this mean all 1 in 10 rifles are crap? NO, but the comparison of the 5,56 twists are completely moot. those twists were designed for stabilizing much longer projo's that were necessary to upgrade the anemic performance of the 55 grain round from shorter M4 barrels. 6.8 doesn't suffer that problem with short barrels, and it derives its top velocity from the use of the proper chamber, rifling geometry and twist. If the 6.8 is going to reach its potential, then using fast twists and SAAMI chambers will ultimately need to fall by the wayside. But, don't take my word for it....MFR's are now waking up and changing their whole lines to include 11 and 12 twist, SPC II and DMR chambers. |
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Your right that I don't hunt with a 6.8, I have my 7mm ultra mag and 300 win mag for hunting duties along with the 6mm rem for light stuff. My 7mm win mag got stolen a few years back and that was my ultimate favorite rifle, bar none. I replaced it with the ultra mag and while it's a killer flat shooter with loads of punch, it's a little too much to enjoy at the range.
My 6.8 is strictly home security, popping coyotes out to 150 yards or so, plinking and conversation, hence the ammo choice. I do realize that the 6.8 is probably one of the best calibers I own and it's a waste on a 10.5" barrel and a 1x reflex sight, although I am also partial to the 7mm round. I intend on building another 6.8 in a 20" to setup for more practical purposes to take advantage of it more. My 5.56s, not really sure what their purpose is anymore, back up home security, more plinking and range duty I guess, which is why I mainly stash TAP and 193 for them. Wherever the market takes the 6.8, I do hope it's in a bigger direction. It is a pretty killer round and has a lot of potential. I don't believe it'll really get a whole lot bigger than it really is due to the lack of military support and mostly well informed AR enthusiasts; there are still loads of AR peeps who are wholly unfamiliar or never even heard of this round. The military support for 5.56 is what has allowed that market to flourish so much. As I don't reload and don't wish to, one of my ultimate main criteria of a caliber is the ability to purchase factory loaded ammo locally and I have a couple choices with the 6.8, actually more than the 7mmRUM. I'm probably wrong on this, it's an assumption/guess so you can answer but, when the 'now inferior' barrel specs first came about, these hotter loads weren't available and as the ammunition advanced, the specs became less beneficial, hence the need to update now, right? |
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Your right that I don't hunt with a 6.8, I have my 7mm ultra mag and 300 win mag for hunting duties along with the 6mm rem for light stuff. My 7mm win mag got stolen a few years back and that was my ultimate favorite rifle, bar none. I replaced it with the ultra mag and while it's a killer flat shooter with loads of punch, it's a little too much to enjoy at the range. My 6.8 is strictly home security, popping coyotes out to 150 yards or so, plinking and conversation, hence the ammo choice. I do realize that the 6.8 is probably one of the best calibers I own and it's a waste on a 10.5" barrel and a 1x reflex sight, although I am also partial to the 7mm round. I intend on building another 6.8 in a 20" to setup for more practical purposes to take advantage of it more. My 5.56s, not really sure what their purpose is anymore, back up home security, more plinking and range duty I guess, which is why I mainly stash TAP and 193 for them. Wherever the market takes the 6.8, I do hope it's in a bigger direction. It is a pretty killer round and has a lot of potential. I don't believe it'll really get a whole lot bigger than it really is due to the lack of military support and mostly well informed AR enthusiasts; there are still loads of AR peeps who are wholly unfamiliar or never even heard of this round. The military support for 5.56 is what has allowed that market to flourish so much. As I don't reload and don't wish to, one of my ultimate main criteria of a caliber is the ability to purchase factory loaded ammo locally and I have a couple choices with the 6.8, actually more than the 7mmRUM. I'm probably wrong on this, it's an assumption/guess so you can answer but, when the 'now inferior' barrel specs first came about, these hotter loads weren't available and as the ammunition advanced, the specs became less beneficial, hence the need to update now, right? Well, no that is not exactly how it happened. Doc GKR can correct me here if I misstate the facts, as he was there, but here is the story as I know it: The ammo was of course designed first, as the AMU decided to build an intermediate caliber round and subsequently, the ammo needed a gun. Because the M4 could easily be retrofitted, they just needed a barrel and someone that could make the ammo. So, they went to Remington and asked PRI to make some barrels, which happened to be Mike Rock 5R blanks in 10 twist. The reason being that no one had ever used anything other than 10 twist for .277 rifles (the .270 Winchester is the only one), so they started with that, simply due to availability, knowing full well that they really should be using 11 or 12 twist. I guess they thought "well, twist rate really shouldn't matter should it, as long as we make the chamber have some extra freebore, like the 5.56 does?" I would have agreed with that back then, but we all found out that wasn't the case. However, you must remember that the original 5R performs differently than does 6 groove CL'd barrels and when you put in the restrictive 10 twist and a tight chamber you hamstring the cartridge due to pressure. The Rock 5r's in 10 twist had a longer chamber than the one Remington and SAAMI gave the market. When they first got ammo from Rem., it was a 115 grain OTM that they claimed could do 2800 FPS from a 24" barrel, and indeed they shot some out of the first 16" specimens that made it to 2750. That, my friend is HOT ammo. But then, the problems started. First, temp sensitivity of the powder made pressure higher. Then Remington released a SAAMI drawing that had a shorter chamber whcih was not in keeping with the Murray / Holland design and the problems got worse. When Remington pulled the ammo, SSA came in and started making ammo that could equal the performance of the original Remington claim. After all, Remington HAD TO BE RIGHT, RIGHT??  Plus, now we all had expectations. Once you release a velocity figure and fire those rounds without blowing up guns, then everyone knows that is what is possible for the round.
What did we get instead? Well, with a SAAMI chamber and 10 twist, guns (model 1's were the quintessential example) were blowing primers and getting cases stuck, and breaking extractors, and the whole thing nearly imploded. That is why, if reloaders had not stepped in and redesigned the entire platform to match the original designer's specs, this thing would have died a slow, ugly death. Moreover, SSA then had to reduce the length of the factory load to 2.26, so that the damn DPMS guns (with chambers even tighter than SAAMI!) wouldn't hurt people. This reduced powder capacity and accuracy since we have found that loading to 2.30" is usually better for accuracy because of less jump to the lands, and it also allows more powder in the case. This = BETTER PERFORMANCE. Now you can understand why I harbor such contempt for the poorly spec'd guns. In the beginning this cartridge wasn't even fully designed, not tested fully by Remington and no formula had been finally decided upon, until we users came along and brought it to its final evolution. I wonder why people think we should have sacrificed all our personal time, effort and money, with the possibility of no reward, simply for mediocrity?
Here's the perfect analogy: imagine 12 gauge shotguns are just being introduced. The designers release the guns with 2 3/4 chambers only. Then steel shot is mandated and there is no 3" magnum, or 3 1/2 chamber available for those that might need it for larger birds like geese. What a cluster%*$@ that could have been. Not everyone needs 3 inch magnum, but you would almost have to be crazy to buy one without that 3" chamber if you hunt anything other than clay pigeons. This is the same thing here. Get the gun that has the most capability, since there is NO DISADVANTAGE to the increased performance specs, even if you perceive that you might not need it, because then it limits the performance for all the rest of us that do. Hey Sredish....I give you a thumbs up for asking....shows objectivity 
ETA: Here's a quote from DocGKR in response to my first ever 6.8 performance test in 2007: DocGKR wrote: Thank you, great job! A couple of things to note: ––Remington advertised 2800 fps for the 115 gr loads out of a 24" test barrel, never out of a 16" barrel weapon. ––The original AMU loaded 115 gr OTM ammo we began testing in 2002 was running up to 2700-2750 fps out of our 16" test weapons without pressure problems; however, these were Mike Rock 5R 1/10 barrels using the original "Murray" chamber, not a SAAMI chamber. ––As stated, the progenitors of 6.8 mm, Steve Holland and Cris Murray, have always felt the 1/10 was too fast and only used it because no other barrel blanks were readily available in early 2002 when the project was first started––1/11 is much better and 1/12 is probably optimal. |
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aah, I didn't realize Remington's initial testing was so hot, I thought I had remembered something in the 2500-2600fps range, not 2750. what an orphaned project through and through. from your story, it's amazing it ever made it this far.
as I always say, Remington should stick to rifles and let the ammunition companies work out the rest.... but in this case, they didn't fair too well in that dept either, sounds like. The important thing is not to stop questioning. Curiosity has its own reason for existing.
-Albert Einstein |
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