Suppressed 308 DPMS Recon (Problem)

daddyflea

daddyflea

Active member
Got my DPMS Recon back from the Factory. Had very high hopes it would return repaired and ready to shoot. Even had Eric at JEP firearms telling me to wait before getting another gun. Well I got it back and my hopes are now gone. This thing was blowing primers shooting Suppressed with heavy Ejector Marks. They sent me a note telling me not to use Reloads and a bunch of test fired brass. To make a long story short they are firing Factory Rounds with Crimped Primers which are trying to blow out and getting Heavy Ejector Marks. Nobody that reloads would be happy with Brass that looks like this. I do not recommend if you are going to be Suppressed ever buying a DPMS in 308. This is the new Gen II Recon that was made to shoot Suppressed as well. I guess if the Factory guys can not make it shoot right I never will. Anybody want to buy a 308 Recon?


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My buddys DPMS 308 16" suppressed and even with a adjustable gas block turned all the way down it is still way over gassed. Even put a heavier buffer in there to try and tame it down.
Is yours a Carbine gas system?
There is a huge difference from his 16" carbine gas to the 18" rifle length i have on my AR10 on recoil. Mine is smooth and soft. His is like shooting a youth model 308 bolt action that only weighs 3#, Its brutal.
 


I have DPMS in 308 and a 243. I run a Specwar with no problems at all.
Factory gas blocks never had to go to anything else.
I shoot 7,62x51 147gr ammo and Winchester 243 100gr.
 
Originally Posted By: NonnieselmanMy buddys DPMS 308 16" suppressed and even with a adjustable gas block turned all the way down it is still way over gassed. Even put a heavier buffer in there to try and tame it down.
Is yours a Carbine gas system?
There is a huge difference from his 16" carbine gas to the 18" rifle length i have on my AR10 on recoil. Mine is smooth and soft. His is like shooting a youth model 308 bolt action that only weighs 3#, Its brutal.

I sent mine back to the factory with the Adjustable Gas Block installed along with an Extra Heavy Buffer with a Matched Heavy Spring. Factory sent it to Alhmons gun Repair who is a Factory authorized repair shop for numerous brands. As you can tell they could not make it act right themselves. I think the short barrel combined with the Carbine length Buffer Tube is just not good for Suppressed 308.
 
have you considered trying a pigtail style gas tube on it? spoof it into acting more like a rifle length gas sytem?


i cannot understand how with an AGB this gun cant be beaten into submission. thats what's baking my noodle on this.

what brand of gas block is it?
 
Sadly, this is a square peg round hole problem. The AR-10/LR-308 platforms are classified as service rifles. They were made for the 7.62x51 cartridge. .308 win commercial ammunition is loaded to higher pressures for bolt action rifles. The 7.62x51 has a sloppier chamber, so the wall thickness of the brass is thicker to keep the brass from splitting. Thicker wall brass means less powder, which means lower pressure. This allows service rifles to cycle and extract faster, while the brass is still expanded, even when the chambers are hot. The tighter tolerances of the bolt action rifles allows for thinner walled cases so more powder. No one is going to cycle a bolt gun fast enough to see the problems that the service rifles will see.

Sadly, there are only a few ways to cure this. One: Go to a high pressure bolt. Many of the bolt manufacturers are running with too much clearance around their firing pins which allows primer flow and holes in primers or even popped primers. I use a Rubber City Armory bolt.
Two: Lower pressure ammunition. In my personal .308 I have found that certain brands are just too hot. I tried some Winchester 150gr Deer XP's and had the same issues as described above, brass swiping, popped primers, holes in primers, etc. But I do not have the same problems with Hornady 150gr SP's. I have never had a problem with mil surplus ammo in 7.62x51. Nor have I had problems with heavier bullets. Heavier bullets mean less powder which means less pressure and less problems.

It may not sound like a good way to fix things, but it is just what we have to do to get them to work right, unless the ammunition manufacturers catch on and start loading service rifle specific ammunition.

Adjustable gas blocks won't solve this problem. They are used to fine tune the cycling through gas control, not to control overpressure of the ammunition.

Just my observations from working with customers rifles over the years.
 
Originally Posted By: Plant.Onehave you considered trying a pigtail style gas tube on it? spoof it into acting more like a rifle length gas sytem?


i cannot understand how with an AGB this gun cant be beaten into submission. thats what's baking my noodle on this.

what brand of gas block is it?

Do you have more information on the Pig Tail Gas System? In my opinion this problem is caused by the Bolt trying to open too early. More Gas Tube could mean a delay and fix the problem. Looking I can find Pig Tails for pistol length but really nothing for a Carbine Lemgth.
 
Originally Posted By: daddyfleaOriginally Posted By: Plant.Onehave you considered trying a pigtail style gas tube on it? spoof it into acting more like a rifle length gas sytem?


i cannot understand how with an AGB this gun cant be beaten into submission. thats what's baking my noodle on this.

what brand of gas block is it?

Do you have more information on the Pig Tail Gas System? In my opinion this problem is caused by the Bolt trying to open too early. More Gas Tube could mean a delay and fix the problem. Looking I can find Pig Tails for pistol length but really nothing for a Carbine Lemgth.


An adjustable gas block will do the same thing as a pig tailed tube, except that you have the ability to adjust it when you need rather than trying to replace the tube every time.

Adjustable gas blocks are not the solution to every problem, but in this case, the early dwell timing of the higher pressure 308, you are correct, adjusting the gas and therefore the bolt timing can help with cycling. But it will not fix popped primers, swiping, or other overpressure issues.
 
case head swipes can be caused by lock time issues. If the bolt is trying to rotate while the case is still swollen to the chamber, with the amount of gas a carbine 308 produces, i have witnessed first hand that this can be the result. I too thought i had pressure issues on the factory ammo i was shooting. turned out not so much.

in my case an AGB was the fix paired with a heavier buffer. I was getting NASTY swipes and pressure signs and the gun was simply running way way way way overgasssed.


and that was before i even suppressed it :X
 
Originally Posted By: SnowmanMoOriginally Posted By: daddyfleaOriginally Posted By: Plant.Onehave you considered trying a pigtail style gas tube on it? spoof it into acting more like a rifle length gas sytem?


i cannot understand how with an AGB this gun cant be beaten into submission. thats what's baking my noodle on this.

what brand of gas block is it?

Do you have more information on the Pig Tail Gas System? In my opinion this problem is caused by the Bolt trying to open too early. More Gas Tube could mean a delay and fix the problem. Looking I can find Pig Tails for pistol length but really nothing for a Carbine Lemgth.


An adjustable gas block will do the same thing as a pig tailed tube, except that you have the ability to adjust it when you need rather than trying to replace the tube every time.

Adjustable gas blocks are not the solution to every problem, but in this case, the early dwell timing of the higher pressure 308, you are correct, adjusting the gas and therefore the bolt timing can help with cycling. But it will not fix popped primers, swiping, or other overpressure issues.

I agree but I do not have over pressure issues. The issue is the bolt opening before it should. This is why the factory rounds had the same issues that my reloads did. They were able to make the factory rounds work because the primers were crimped in but it was easy to see they were trying to pop and the swipes on the ejector were very evident.
 
Originally Posted By: daddyfleaOriginally Posted By: SnowmanMoOriginally Posted By: daddyfleaOriginally Posted By: Plant.Onehave you considered trying a pigtail style gas tube on it? spoof it into acting more like a rifle length gas sytem?


i cannot understand how with an AGB this gun cant be beaten into submission. thats what's baking my noodle on this.

what brand of gas block is it?

Do you have more information on the Pig Tail Gas System? In my opinion this problem is caused by the Bolt trying to open too early. More Gas Tube could mean a delay and fix the problem. Looking I can find Pig Tails for pistol length but really nothing for a Carbine Lemgth.


An adjustable gas block will do the same thing as a pig tailed tube, except that you have the ability to adjust it when you need rather than trying to replace the tube every time.

Adjustable gas blocks are not the solution to every problem, but in this case, the early dwell timing of the higher pressure 308, you are correct, adjusting the gas and therefore the bolt timing can help with cycling. But it will not fix popped primers, swiping, or other overpressure issues.

I agree but I do not have over pressure issues. The issue is the bolt opening before it should. This is why the factory rounds had the same issues that my reloads did. They were able to make the factory rounds work because the primers were crimped in but it was easy to see they were trying to pop and the swipes on the ejector were very evident.

Didn't I read in your post that you already had installed an adjustable gas block though? So how would a pigtail gas tube help if you already have a gas regulating system on it? If I read incorrectly, I apologize. But if you have an adjustable gas block on it already, and you are still having problems, then timing should not be the issue as the block can be used to set the timing.

I used to get popped primers on my mid length gas, .308, running a rifle buffer with an adjustable gas block. I could choke down my gas so that the gun wouldn't cycle, but I still got pierced and popped primers. It was consistent. First I would get pierced primers and if I kept shooting, then they started popping as the gun got hot. Let her cool down and it would all start over again. That was with 150gr ammunition. When I would shift to 165gr or 168gr ammunition the problem went away. No matter what I do to the gas block, the problem persisted.

I saw that you wrote that this happened with hand loads as well as factory. Sounds like you got a hold of a lemon to me. There is something fundamentally wrong with that rifle to cause this. Something that even they are missing.

Sorry to hear about your troubles.
 
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