AR10T Dedicated suppressed upper thoughts

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13 years 6 months ago #7669 by crux
AR10T Dedicated suppressed upper thoughts was created by crux
I'm going to put this under suppressor even though it's more of an upper construction question. I've been considering getting a 20 inch heavy barrel for my AR10T carbine. I've looked at the Armalite SASS upper, and am familiar with the adjustable gas system which Armalite recommends switching between every 100 rounds or so for clean out. I'm wondering if a dedicated upper could be assembled that could handle persistent suppressor operation. I'm wondering if you'd have to go piston for cleanliness or if you could use direct impingement. Any thoughts?

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13 years 6 months ago #7672 by LebbenB
Replied by LebbenB on topic Re: AR10T Dedicated suppressed upper thoughts
The big issue with DI guns and cans is back pressure or "blowback." DI guns have more back pressure than a piston gun, it's just a matter of where excess gas is vented. On a piston gun, excess is vented by the gas collar/block or along the op-rod housing. In a DI gun, the excess gas is vented into the chamber/receiver. Back pressure from a supressor compounds this accumulation. This additional accumulation of residue increases quickly when firing sustained strings, to the point of choking the gun after 120-150 rounds(In my experience, I need to add.) Heavy strings of supressed fire were the driving force behind grafting a piston system onto the AR platform.

Supressed precision rifles are a different ballgame. They'll (usually) never see sustained strings of fire between maintenance sessions the way a carbine/assault rifle would, so the build-up of residue would proceed at a much slower pace. I would wager the reason Armalite advises the user to change the setting every 100 rounds or so is to let the rifle "blow out" any residue in the barrel or the gas tube.

With a suppressor mounted, most rifles show a pretty substantial POI shift. It's recommended that the user leave the can on the rifle once he has his sights/optics zeroed for the use of a supression system, dismounting it only for maintenance.

While a piston system would retard the build up of residue, it won't get rid of it entirely. If you don't mind a little soot on your face after shooting, stay with a DI upper with a PRI GasBuster charging handle. If you don't, go with a piston system. The piston system will be a bit heavier, due to more mass over the barrel, which might be a deal breaker given your plans for a heavy barrel. A quality piston upper will also be several hundred dollars more expensive than a comparable DI upper.

HTH

Leb

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13 years 2 months ago #8840 by txlongshotb4
Replied by txlongshotb4 on topic Re: AR10T Dedicated suppressed upper thoughts
I'd stick with the DI system for a dedicated long gun upper. When I built mine, I opted to try something a little outside of the box that has proven to work well. I used an adjustable gas block, but instead of relying on choking off the impingement, I beefed up my action. I installed a superior shooting solutions heavy flat coil spring, and a superior shooting solutions bolt cam counter weight. I also switched out my buffer with an Enidyne hydraulic buffer to take up some of the impact. The result is that I can almost "full bore" my gas tube-which blows out a lot of the residual.
Yeah, it does get dirty-but that's the nature of the beast with a suppressor. I've yet to run it to the point of failure, and I've run it pretty hard-100+ rounds of M118LR without so much as a patch...no kidding. I have heard some horror stories about running suppressed 7.62 guns with piston drives. It is cleaner, but it also cycles hard with the extra pressure from the can-so if you don't get it right, you can really damage your gun.

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13 years 2 months ago #8843 by mlotziii
Replied by mlotziii on topic Re: AR10T Dedicated suppressed upper thoughts
I've thought about having a dedicated suppressed upper built on several occasions. To solve all the problems with gas my plan was to have the gas system shutoff and only shoot it single shot.

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13 years 2 months ago #8850 by LebbenB
Replied by LebbenB on topic Re: AR10T Dedicated suppressed upper thoughts

...I installed a superior shooting solutions heavy flat coil spring, and a superior shooting solutions bolt cam counter weight. I also switched out my buffer with an Enidyne hydraulic buffer to take up some of the impact. The result is that I can almost "full bore" my gas tube-which blows out a lot of the residual.

So you slowed down the cycle in order to gve the system more time to vent itself?

Any undue/unforseen wear on the BCG, receiver or receiver extension? I would imagine such a mod also greatly reduced perceived recoil.

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13 years 1 month ago #9156 by txlongshotb4
Replied by txlongshotb4 on topic Re: AR10T Dedicated suppressed upper thoughts
I did slow down the cycle, but venting had nothing to do with my intent. I guess now that you've mentioned it, I believe that very phenomenon has been a bi-product of the system I have created, but the actual intent was just to slow down the lock-time and to reduce the action movement until the round cleared the muzzle. As for the fouling and mechanical wear, my bolt carrier group is all but pristine. The only wear I've found on it has been purely mechanical where the metal to metal contact is inevitable. My rifle cycles "very slow"...when your ear is to the stock, you can hear the buffer spring, and it is quite delayed...quite. I could outrun this trigger in a heartbeat.-But this is a precision gun, not a race gun.

The downfall of this system is that it gets dirty-REALLY dirty...but it transfers carbon evenly throughout the upper receiver on account of having the gas block wide open, so there is not a lot of apparent build up on any of the proprietary individual components. Even when it is absolutely filthy, it will still shoot, and the apparent shift in accuracy is minimal,but after 100 rounds or so the forward assist is my buddy...Because you simply cannot have your cake and eat it too!

As for recoil, it is certainly a pussy cat.

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