Reducing blowback with a suppressed AR?

[SDguy]

Get this out in the open right up front. Personally I have never been an AR fan, or at least not yet. Seems like most arguments I come up with to stay away from the AR type weapons I generally debunk in rather short order, Still little to no love for the platform yet

6.5 Grendel & 6mm ARC have recently been my favorite calibers, though in a mini Bolt action. Was not long ago a co-worker shared a piece of range fired 6mm ARC brass with me that was fired in a suppressed AR. He was sharing with me that that based on the sooty case the weapon was defiantly supressed. Guess I have been living under a rock as this was news to me.

So I am doing a little digging & see a bolt carrier marketed by GemTech UPC:609224347825 is touted to reduce this blow back in a big way in a 223 for example. This begs the question, what may a guy do to reduce the blowback in a AR type 6.5 Grendel or 6mm ARC?

Thanks in advance for sharing!

[montana]

Get this out in the open right up front. Personally I have never been an AR fan, or at least not yet. Seems like most arguments I come up with to stay away from the AR type weapons I generally debunk in rather short order, Still little to no love for the platform yet

6.5 Grendel & 6mm ARC have recently been my favorite calibers, though in a mini Bolt action. Was not long ago a co-worker shared a piece of range fired 6mm ARC brass with me that was fired in a suppressed AR. He was sharing with me that that based on the sooty case the weapon was defiantly supressed. Guess I have been living under a rock as this was news to me.

So I am doing a little digging & see a bolt carrier marketed by GemTech UPC:609224347825 is touted to reduce this blow back in a big way in a 223 for example. This begs the question, what may a guy do to reduce the blowback in a AR type 6.5 Grendel or 6mm ARC?

Thanks in advance for sharing!

All that BCG does is reduce the gas into the bolt carrier piston when using a suppressor. Using a suppressor can over gas the AR gas system, increasing the bolt carrier velocity. Instead of using an adjustable gas block, "which controls the gas at the barrel port" this does it at the bolt carrier...Why you dislike the AR rifle is another subject...

[burnsy13]

I have a Bootleg adjustable carry in my primary 5.56 AR. It works, but not nearly as effectively as an adjustable gas block IMO. Inside the receivers gets pretty dirty with it. I like it, it's simple, but I have adjustable gas blocks on my 2 Grendels, an 18" RLGS and a 12" SBR. Both are full-time suppressed, adjustable gas block with smaller increments to limit gas flow and tune to your ammo is more effective.

[Fess]

Silencerco has recently introduced a charging handle with a gasket on it. They call it " the Gas Defeating Charging Handle (GDCH)". I have no idea how well it really works.
https://silencerco.com/silencers/gas-def...ng-handle/

[LRRPF52]

Get this out in the open right up front. Personally I have never been an AR fan, or at least not yet. Seems like most arguments I come up with to stay away from the AR type weapons I generally debunk in rather short order, Still little to no love for the platform yet

6.5 Grendel & 6mm ARC have recently been my favorite calibers, though in a mini Bolt action. Was not long ago a co-worker shared a piece of range fired 6mm ARC brass with me that was fired in a suppressed AR. He was sharing with me that that based on the sooty case the weapon was defiantly supressed. Guess I have been living under a rock as this was news to me.

So I am doing a little digging & see a bolt carrier marketed by GemTech UPC:609224347825 is touted to reduce this blow back in a big way in a 223 for example. This begs the question, what may a guy do to reduce the blowback in a AR type 6.5 Grendel or 6mm ARC?

Thanks in advance for sharing!

I use Bootleg Adjustable Gas Carriers now for this reason. Bootleg has a 4-position choke that can be rotated with a small flathead through the ejection port, which is one of the most user-friendly adjustable gas systems available for shooting suppressed.

[LRRPF52]

Silencerco has recently introduced a charging handle with a gasket on it. They call it " the Gas Defeating Charging Handle (GDCH)". I have no idea how well it really works.
https://silencerco.com/silencers/gas-def...ng-handle/

The offensive and toxic gas that emanates from the AR-15 and other gas-operated actions comes almost entirely from the breech.

It does it on external op-rod piston actions as well.

[Klem]

SD,

Not much you can do to stop gas leaking around the case back into the receiver other than not to use a suppressor, and in low loads, make sure there are no splits at the neck that will stop it from sealing (faiure to obdurate).

You can use an adjustable gas block or adjustable carrier to manage some of the gas/soot spewing into the receiver but it still needs to go all the way back and lock on last round. That said, if you use a piston upper where no gas/soot comes into the receiver from the gas system, and with a suppressor, you will still find the gun and spent cases just as filthy as if was a direct impingement gas system. The reason for this is that most of the sooty gas comes back into the receiver from the chamber, not the gas system. It bleeds around the neck of the case back into the receiver when the case unseals as the pressure drops.

Your friend is right, filthy cases are a sign of a suppressor, as is all the soot that gets everywhere regardless of your AGB setting. I just sleuth it out with WD40 and a paper towel. The cases get an ultrasonic bath which is more of a pain than just tumbling, but hey. The gasket charge handle is not going to change much given how filthy it gets with a piston. I see Radian now sell a 'Silencer Optimised' charge handle however being a left-hander and knowing how much spit comes through the ejection port from the chamber I don't think it will do much.

If you need more proof that most pressurized soot comes back from the chamber and very little from the gas system, look at the spent cases of H&K weapons like the PSG-1 and MP5's. H&K cut tiny parallel channels into their chambers to aid extraction. The case expands and seals but the pressurized channels then aid in unsealing. Check out how dirty they are without a suppressor. Suppressors make it worse by pushing that soot back into the receiver more.
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A device purpose-built to reduce blowback would be something like a 'bore evacuator' (fume extractor) on tanks. But I have never seen them in small arms.

[SDguy]

So my take away is the only way to nearly eliminate the blowback when using a suppressor, is to compleatly shut down the gas - in the case of an adjustable gas block. This of course would eliminate the semi auto advantage.
Another take may be if we were able to delay the bolt opening by a few micro-seconds the blowback may be reduced, though by no means eliminated.

Thanks for the input all, really apreciate your shared experience.

[Klem]

Correct, to stop positive pressure pushing soot back into the receiver wait until the pressure drops.

You could also experiment with powders to see which one is the cleanest - but that is a luxury nowadays.

[LRRPF52]

So my take away is the only way to nearly eliminate the blowback when using a suppressor, is to compleatly shut down the gas - in the case of an adjustable gas block. This of course would eliminate the semi auto advantage.
Another take may be if we were able to delay the bolt opening by a few micro-seconds the blowback may be reduced, though by no means eliminated.

Thanks for the input all, really apreciate your shared experience.

Another more common approach in some suppressor designs is what are called “flow-through” suppressors that reduce accumulated back pressure. They also tend to be louder than efficient cans.

[Double Naught Spy]

I use Bootleg Adjustable Gas Carriers now for this reason. Bootleg has a 4-position choke that can be rotated with a small flathead through the ejection port, which is one of the most user-friendly adjustable gas systems available for shooting suppressed.

My gunsmithing skills are minimal. I have two of these that have been very beneficial to overgassed guns. As noted above, they are not as refined as an adjustable gas block, but they can certainly improve one's situation quite readily.

I would buy again.

[SDguy]

My gunsmithing skills are minimal. I have two of these that have been very beneficial to overgassed guns. As noted above, they are not as refined as an adjustable gas block, but they can certainly improve one's situation quite readily.

I would buy again.

Is the adjustable glass carrier meant to be used with an adjustable gas block or instead of? Pros & cons?

[Double Naught Spy]

If you have an adjustable gas block, you should not need an adjustable carrier.

[LRRPF52]

Ruger’s new SFAR introduces a feature that is meant to handle catastrophic events by venting out gas like on a 1893 Mauser and subsequent bolt actions many are familiar with.

A byproduct of this feature is that escaping gases from the back-pressure flowing from suppressors vents out that set of holes, before the bolt fully retracts from within the extension.

Check this out:



It also has 4 vent holes in the bolt carrier on the RH side, clocked with the ejection port to help escaping gases flow through and dissipate through those, as to avoid splitting the carrier open in the event of a case rupture in-battery.