Specific can for over-gassed AR

[fullm3taljacket]

I was one of those who ordered one of the Geissele Duty Upper Receivers on Black Friday 2019. The 18 week wait time was worth it as it is accurate and durable. In searching the specs for the upper's gas port while waiting, a G rep. said that it was .068 which should be perfect for an 11.5" carbine system. This build was going to be run with a can only, so I also got one of their ACHs, an H2 buffer, and a Bootleg adj. BCG. Turned all the way down, it functions with brass 55gr - 77gr stuff but with the steel cased stuff, I have to turn it all the way open. To me this indicates this is highly effective. Lastly, I did the silicon gasket around the CH. I chose the YHM Turbo K which I use on several guns and rather like.

My issue is that even with all of this mitigation, it is EXTREMELY gassy, as in more than two rounds is a choking hazard. I do not want an adj. gas block and will not put one on a duty-grade gun, but I would be interested in opinions as far as any other available options. For example, I have been thinking about getting one of the full sized steel OSS .30 cal cans to both add volume, flow-thru, and bore diameter as likely the last real measure I could take within what I am comfortable doing with this particular blaster. Open to suggestions.

 

[Snuby642]

Suggest you modify your stance on an agb.

Stop banging your head against a wall.

I fought using one for a long time.

I was a stubborn sob.
Never again.

Imho

 

[fullm3taljacket]

Suggest you modify your stance on an agb.

Stop banging your head against a wall.

I fought using one for a long time.

I was a stubborn sob.
Never again.

Imho

The BCG is doing the exact same thing anyway, that is quantifiable. Turning the gas flow down more would make it unreliable anyway, so what use is it then? I've installed and used them before, I just won't use one on a duty gun.

 

[Snuby642]

If your adjustable bcg was taking care of the root problem this wouldn't be a conversation.

But it's not and here you are.

And I'm not arguing brands of your existing equipmemt or anything like that.

I have barrels from 20 to 10.5 different brands and 5.56, 6.5 and 30 cal with 5.56 and 30 cal cans for them that would be relevant.

None of that matters other than been there.

Just hate to see people waste thier time.
I'll say no more, good luck sir.

 

[fullm3taljacket]

If your adjustable bcg was taking care of the root problem this wouldn't be a conversation.

But it's not and here you are.

And I'm not arguing brands of your existing equipmemt or anything like that.

I have barrels from 20 to 10.5 different brands and 5.56, 6.5 and 30 cal with 5.56 and 30 cal cans for them that would be relevant.

None of that matters other than been there.

Just hate to see people waste thier time.
I'll say no more, good luck sir.

The primary goal is reliability. I never said the Adj. BCG solved the problem, just that it functions as designed. I have quantified that the Adj. BCG does work in turning down the amount of gas allowed into the system, but does not solve the problem. I also know that turning the gas down more will make it unreliable. Therefore it helps the problem but does not solve it. Going down your path would make it not be the one thing it must be, which again does not solve the problem. Nothing personal...the problem may not be solvable at all, but as indicated, I am not putting an adj gas block on this, as I led off with.

 

[J McGriddle]

As you said, it is a duty grade upper- it will be over gassed. An adjustable BCG is not as effective as an adjustable gas block. Since you are adamantly opposed to an adjustable gas block you really only have one option, a flow thru suppressor like the OSS.

 

[fullm3taljacket]

As you said, it is a duty grade upper- it will be over gassed. An adjustable BCG is not as effective as an adjustable gas block. Since you are adamantly opposed to an adjustable gas block you really only have one option, a flow thru suppressor like the OSS.

Ok, so at least i'm thinking through the steps appropriately. "Effective" means different things to different people. I am saying it does what it says it will do. Of course the range of adjustment is inferior to the GB solution, but I'm not looking for infite adjustability, but a gross, simple, rugged solution that can very easily be changed on the fly if necessary. Thanks for the input, it is appreciated.

 

[sam4886]

The only way to get less glass at the reciever, and thus into your eyes, is to reduce the flow at the block. You could also add a shit load of reciprocating mass to slow down cycling, I guess.

Where do you think the adjustable BCG vents gas to? Gotta go somewhere right around your face....

If you want a "duty grade" gun, part of that is a shit load of gas so it'll cycle when properly tuned guns won't.

You posted while I was typing about a few gross adjustments. There are AGBs your there designed for what you're thinking. The manufacturer is escaping me right now, but one is called the switch block I think.

 

[fullm3taljacket]

The only way to get less glass at the reciever, and thus into your eyes, is to reduce the flow at the block. You could also add a shit load of reciprocating mass to slow down cycling, I guess.

Where do you think the adjustable BCG vents gas to? Gotta go somewhere right around your face....

If you want a "duty grade" gun, part of that is a shit load of gas so it'll cycle when properly tuned guns won't.

Right. No disagreement. I'm asking if there are any other measures not already discussed that I might have missed.

 

[Eustice]

I’m not sure why you’re against an adjustable gas block. An SLR with clicks from a detent seems pretty reliable. Get it set then count the clicks from closed. Keep an appropriate allen in the grip.

Also, you seem to have a lot of conflicting things in the original post.

You say you won’t use an AGB in a duty gun because it is unreliable. But you say more than two rounds of steel cased causes a choking hazard and you can’t fire more than that at a time. So you’re trading a possibly unreliable AGB for a known two shot rifle.

It runs brass cased ammo fine but not steel. Are you going to use steel cased ammo in your duty weapon? How is that weapon going to hold up over an extended period of steel cased ammo versus brass if there is an absence of time to keep it clean? Steel ammo is great for blowing holes in water heaters and old washing machines. I suppose it also gives a beacon of your location. People just follow the smell of cat piss.

What type of duty are we talking about here? Is it going to Marjah? Does it ride in a patrol car? Is it bump-in-the-night duty? Steel cased can have problems all on their own. For a duty gun why are you not using better ammo? Or is this the whole “if it can’t eat steel it doesn’t deserve brass” argument?

 

[fullm3taljacket]

I’m not sure why you’re against an adjustable gas block. An SLR with clicks from a detent seems pretty reliable. Get it set then count the clicks from closed. Keep an appropriate allen in the grip.

Also, you seem to have a lot of conflicting things in the original post.

You say you won’t use an AGB in a duty gun because it is unreliable. But you say more than two rounds of steel cased causes a choking hazard and you can’t fire more than that at a time. So you’re trading a possibly unreliable AGB for a known two shot rifle.

It runs brass cased ammo fine but not steel. Are you going to use steel cased ammo in your duty weapon? How is that weapon going to hold up over an extended period of steel cased ammo versus brass if there is an absence of time to keep it clean? Steel ammo is great for blowing holes in water heaters and old washing machines. I suppose it also gives a beacon of your location. People just follow the smell of cat piss.

What type of duty are we talking about here? Is it going to Marjah? Does it ride in a patrol car? Is it bump-in-the-night duty? Steel cased can have problems all on their own. For a duty gun why are you not using better ammo? Or is this the whole “if it can’t eat steel it doesn’t deserve brass” argument?

I would contend that a GB solution is less reliable than the BCG solution, but not as good at gas mitigation. Everything has a trade-off. I didn't say GB solutions were garbage or criticize anyone else for having them. Anyone can do what they want, but I'm doing it this way. If you disagree, hey, cool, but that's not helping me, that's just criticizing. I know I have put myself into a corner, and I'm ok with that. If I am, everyone else should be too. This isn't about what anyone else would do with their build, it's about options for mine. That's why I came here, because I figured y'all might have additional data points. Needless to say, I am not going to a GB solution.

I was being slightly feceitious about choking, but it isn't pleasant. After a shot or two, give it one second it's not a problem but 5-10 round strings are difficult, not that those need to happen almost ever. You also misinterpret what I said about ammo/I didn't fully describe the ammo-running I had expereinced. I can run brass at any gas position but steel has to be run full open.

 

[Eustice]

Could the gas be mitigated by a different charging handle such as a PRI gas buster?

edit: I read all the items you had again and you said you were using a Geissele ACH. Perhaps try a different charging handle to see if it’s better or worse.

 

[fullm3taljacket]

Could the gas be mitigated by a different charging handle such as a PRI gas buster?

edit: I read all the items you had again and you said you were using a Geissele ACH. Perhaps try a different charging handle to see if it’s better or worse.

It certainly couldn't hurt...got my eye out for a Radian SD, in stock and for less than $100, but not holding my breath anytime soon.

 

[Lone star Shooter]

My Noveske AR-15 has the switchblock gas block which restricts (throttles) the gas block opening the switched to “suppressed” mode. It does make a difference in the amount of gas blowback with a suppressor. The rifle will run over gassed in normal mode but realizability is 100% either way With the suppressor.

You just have to remember to switch the gas block to the mode you want.

Or practice holding your breath