Adjustable BCG

[Hoons]

Looking to tame the gas blowback when shooting suppressed on my 11.5" pistol.

Does bootleg version expel gas out the side via the holes in the BCG. Any out there that simply restrict the gas that enters BCG? I'm leaning towards Sharps bcg because it seems to do so and seems like better quality. Anyone with experience with either of these?

 

[Bertfish]

Why not use an adjustable gas block?

 

[engineerbrian]

Why not use an adjustable gas block?

I agree. I had an adjustable BCG and ended up getting rid of it. Adjustable gas block was so much easier.

 

[aervin]

I agree with the above, I'd go with an adjustable gas block. I like the Superlative Arms stuff since you can choose to go either restrictive or bleed off.

 

[DutchV]

Or use one of the restricted gas tubes from Black River Tactical. No adjustments or maintenance required once it's installed.

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[outrider58]

Agree with all the above responses.

 

[schnauzr]

I have heard of an instance where a manufacturer of a complete rifle recommended the use of an adjustable carrier as a means of taming suppressed blowback, as customer-replacing the factory pinned non-adjustable gas block would void the warranty. So, OP may not have that option. Considering this being the case, which is the recommended adjustable carrier?

 

[outrider58]

Looking to tame the gas blowback when shooting suppressed on my 11.5" pistol.

Does bootleg version expel gas out the side via the holes in the BCG. Any out there that simply restrict the gas that enters BCG? I'm leaning towards Sharps bcg because it seems to do so and seems like better quality. Anyone with experience with either of these?

Any noticeable restriction would have to start at the gas block, either in the gas block or where it enters the gas tube. Anything behind that is the full shot of hot gas into the carrier and it has to go somewhere. It could also result in higher bolt carrier speeds, so now you're trying to tame that with heavier buffers and buffer springs.

Adjustable gas blocks will actually allow you to tame down the entire cyclic impulse of the gun, as well as cut the hot gasses.

 

[Hoons]

Adjustable gas blocks seems like a failure point vs non-adjustable for heavy round count use rifle.

 

[John from MD]

Adjustable gas blocks seems like a failure point vs non-adjustable for heavy round count use rifle.

What do you base this on? I have a couple that are full auto and never had a problem with the AGB.

 

[woodline]

To OP:

Why are you suppressing your rifle? There are several reasons to do so: noise moderation (either to the user or to people nearby), signature reduction, and to look cool tend to be the typical reasons. If you’re only interested in the third, an adjustable carrier is fine. Adjustable carriers can be fine in other cases, for instance if you already have an adjustable gas block and want to slightly tweak things at the carrier for different loads without adjusting a gas block (say you only have a two position gas block). They can help if you just need to slightly tweak your system timing, but at a significant cost.

If you care about your health and your ears, you should be aware that an adjustable carrier shoots high pressure jets of gas out the port. They can increase at ear sound pressure levels significantly and cause you to breathe in just about as much gas as if you were not using an adjustable carrier. In some cases it’s so bad that you might as well be using a blast shield that redirects flash and noise forward.

 

[Hoons]

To OP:

Why are you suppressing your rifle? There are several reasons to do so: noise moderation (either to the user or to people nearby), signature reduction, and to look cool tend to be the typical reasons. If you’re only interested in the third, an adjustable carrier is fine. Adjustable carriers can be fine in other cases, for instance if you already have an adjustable gas block and want to slightly tweak things at the carrier for different loads without adjusting a gas block (say you only have a two position gas block). They can help if you just need to slightly tweak your system timing, but at a significant cost.

If you care about your health and your ears, you should be aware that an adjustable carrier shoots high pressure jets of gas out the port. They can increase at ear sound pressure levels significantly and cause you to breathe in just about as much gas as if you were not using an adjustable carrier. In some cases it’s so bad that you might as well be using a blast shield that redirects flash and noise forward.

That was the reason for my initial question. Bootleg BCG vents it to the side but Sharps seems to restrict it via set screw in the gas key. Are you sure the sharps vents it to the side ports?

If I install AGB like the superlatives, how would one make adjustments if the handguard extends 2-3 inches beyond the gas block?

 

[schnauzr]

That was the reason for my initial question. Bootleg BCG vents it to the side but Sharps seems to restrict it via set screw in the gas key. Are you sure the sharps vents it to the side ports?

If I install AGB like the superlatives, how would one make adjustments if the handguard extends 2-3 inches beyond the gas block?

I had an SLR Sentry 7 and all I needed was an extra long hex key to tune it. Was a mid-length gas system under a 15" handguard. I had the kind with a T-handle but I'm sure there are other types.

 

[outrider58]

I had an SLR Sentry 7 and all I needed was an extra long hex key to tune it. Was a mid-length gas system under a 15" handguard. I had the kind with a T-handle but I'm sure there are other types.

Superlatives come with a 4"-5" hex key also.

I've found that I rarely, make that almost never adjust my GBs once I set them. I'm not super picky that way.

 

[John from MD]

Superlatives come with a 4"-5" hex key also.

I've found that I rarely, make that almost never adjust my GBs once I set them. I'm not super picky that way.

This. Once you adjust for your load, you don't need to bother with it anymore.

 

[woodline]

That was the reason for my initial question. Bootleg BCG vents it to the side but Sharps seems to restrict it via set screw in the gas key. Are you sure the sharps vents it to the side ports?

If I install AGB like the superlatives, how would one make adjustments if the handguard extends 2-3 inches beyond the gas block?

No you’re right, I should have specified that I was talking about bootleg (or the old gemtechs).

I haven’t personally used the sharps, but adjustable gas keys (which the sharps appears to use) theoretically restrict gas at the key and push it out the front of the upper receiver. That’s kind of what happens, but also a fair amount leaks into the action. So it will fix timing issues, but you’re still going to get gas and some pop, just slightly farther forward.

The gas has to go somewhere, and the place you want it to go is down your barrel and out the front of your rifle, generally speaking. Restricting gas at the gas block has the benefit of limiting flow back into the action at the source, and fixes the same timing issues you’d be fixing with an adjustable bcg.

If you’re not ready to commit to an adjustable gas block (adjustable gas blocks do have drawbacks, and not everyone wants to change gas blocks anyway), suggest you contact BRT with your build specs and they’ll help you choose a gas tube.

 

[woodline]

OP, what kind of 11.5” pistol do you have? Did you build or buy? What kind of barrel is it? Is it 5.56? What kind of suppressor do you have?

What specific issues are you having with your setup now?

 

[clandestine]

Suppressed semi automatic and full automatic guns shoot most gas out of the chamber, not the gas system.

Debating what direction the gas is redirected is one of the strangest things I have ever heard.

If you are concerned about health and gas blowback then stop shooting guns.

 

[outrider58]

Shooting guns is dirty work. No getting around that.

 

[woodline]

Suppressed semi automatic and full automatic guns shoot most gas out of the chamber, not the gas system.

Debating what direction the gas is redirected is one of the strangest things I have ever heard.

If you are concerned about health and gas blowback then stop shooting guns.

That’s certainly one perspective on it. I would say it depends on the suppressor (there are cans that specifically mitigate back pressure, and how much gas goes back through the barrel depends on how early the excess back pressure that does make it through the gas tube causes the system to unlock), and whether or not you’re putting the suppressor on your gun to make it quieter. Adjustable BCGs can add on the order of 5-10 decibels worth of port pop to a poorly configured setup.

Maybe those concerns don’t matter to you, but they do to me. I get enough of this garbage at work, consequently I try to minimize it with my personal firearms.