Newbie AR15 suppressor question. How much back pressure can be eliminated?

[nikdanja]

I’ve always read about back pressure in ARs that are suppressed, but damn! I have an adjustable gas block that’s adjusted correctly for the can but I feel like that doesn’t do anything. My buddy tried the gas buster charging handle and didn’t like it. He runs one of those adjustable BCGs with no adjustable gas block.

I guess my question is, what the best way to eliminate the most gas?

I’m using really light hand loads. 55b at 2550 FPS

 

[Clayman]

I’ve always read about back pressure in ARs that are suppressed, but damn! I have an adjustable gas block that’s adjusted correctly for the can but I feel like that doesn’t do anything. My buddy tried the gas buster charging handle and didn’t like it. He runs one of those adjustable BCGs with no adjustable gas block.

I guess my question is, what the best way to eliminate the most gas?

I’m using really light hand loads. 55b at 2550 FPS

What suppressor do you have?

Where are you ejecting?

What barrel and gas length do you have?

Short dwell length is the best way to eliminate gas.

Adjusting gas and mass will certainly help but if you have a long dwell length you're pretty much sol unless you buy a low back pressure suppressor like an OSS, Sandman K, Helios dt.

 

[FCS]

Correctly size port.
Correctly position port.
Use low back pressure can.
Buffer weight.
Buffer spring K.


55 @ 2550 is less than I’m getting w/60 Vmax out of suppressed 10.5” SBR.

Would be helpful to know:
Barrel length
Gas system length
Port size
Buffer weight
Buffer spring
Can used
Powder used

More that is known about current configuration, better suggestions can be made.

 

[nikdanja]

What suppressor do you have?

Where are you ejecting?

What barrel and gas length do you have?

Short dwell length is the best way to eliminate gas.

Adjusting gas and mass will certainly help but if you have a long dwell length you're pretty much sol unless you buy a low back pressure suppressor like an OSS, Sandman K, Helios dt.

10.5” barrel (223)
Carbine length gas system
Not sure where I’m ejecting
Sandman S can

 

[nikdanja]

Correctly size port.
Correctly position port.
Use low back pressure can.
Buffer weight.
Buffer spring K.


55 @ 2550 is less than I’m getting w/60 Vmax out of suppressed 10.5” SBR.

Would be helpful to know:
Barrel length
Gas system length
Port size
Buffer weight
Buffer spring
Can used
Powder used

More that is known about current configuration, better suggestions can be made.

Correctly size port.
Correctly position port.
Use low back pressure can.
Buffer weight.
Buffer spring K.


55 @ 2550 is less than I’m getting w/60 Vmax out of suppressed 10.5” SBR.

Would be helpful to know:
Barrel length
Gas system length
Port size
Buffer weight
Buffer spring
Can used
Powder used

More that is known about current configuration, better suggestions can be made.

10.5” 223 barrel
Carbine length has system
Carbine buffer and regular spring
Sandman S can
H335 powder

 

[CaptArab]

Trigger warning- this post will piss folks off and net me 1001 instructions on how real men build rifles.

If I had to start my stamp collection all over (nearly a dozen), I'd buy TBACs for my bolt guns and nothing but OSS for gas guns.

 

[AMGtuned]

I went with AGB (all but closed), H3 buffer, heavy buffer spring (the one from some guys Franklin BFS3), on my 10.5. 6.5"x1.625" form 1 can. This cured my ejection pattern, and removed any bothersome gas blowback.

 

[Clayman]

10.5” 223 barrel
Carbine length has system
Carbine buffer and regular spring
Sandman S can
H335 powder

Well next time you are out pay attention to your ejection pattern. I'd also be curious of how your gun functions with factory ammo. Too many variables for hand loads for me to offer an opinion on that and I'm not that experienced in that aspect anyway.

Try an h2 or h3 buffer and re-adjust your gas block by closing it completely and shooting 1 round at a time until the bcg locks back. If you don't mind spending the money get the Vltor A5 system (H2 or H3) with a springco green. Lmt enhanced carrier should help delay unlocking and be beneficial as well but they are extremely difficult to come by atm.

As a complete system the Surefire OBC would also be beneficial but like the lmt they are extremely difficult to get atm.

The Sandman S isn't a particularly high back pressure suppressor. 10.5 doesn't have that long of a dwell length but it's not quite optimized for suppressor use in terms of minimizing gas and delaying unlocking. It shouldn't be that bad though.

Are you using the .30 cal end cap or 5.56? Use the 30 if you aren't.

 

[FCS]

10.5” 223 barrel
Carbine length has system
Carbine buffer and regular spring
Sandman S can
H335 powder

CAR H3 buffer would be helpful.
Orange buffer spring from Springco wouldn’t hurt you any.

What other powders are available?

 

[Clayman]

Trigger warning- this post will piss folks off and net me 1001 instructions on how real men build rifles.

If I had to start my stamp collection all over (nearly a dozen), I'd buy TBACs for my bolt guns and nothing but OSS for gas guns.

OSS is definitely the easy route on semi autos. You certainly can do better but you do have to build with a purpose. It would be nice to be able to start over. I think I'd only keep 3 maybe 4 cans that I currently have.

I can't wait to see Jay's pewscience testing on a tuned host (11.5 midlength, Surefire obc, adjustable gas block) vs the mk18 data. The mk18 has already shown on an unturned host the OSS will be quieter at the ear vs everything else. There are only a couple more cans I care to see mk18 data on but they are also very low back pressure.

 

[Delicatessen]

Yeah that’s the issue with suppressors, it’s hard to try things out. If I had it to do over I would do oss for semi auto, tbac for bolt, pistol caliber has a few good options rugged is one.

 

[nikdanja]

Well next time you are out pay attention to your ejection pattern. I'd also be curious of how your gun functions with factory ammo. Too many variables for hand loads for me to offer an opinion on that and I'm not that experienced in that aspect anyway.

Try an h2 or h3 buffer and re-adjust your gas block by closing it completely and shooting 1 round at a time until the bcg locks back. If you don't mind spending the money get the Vltor A5 system (H2 or H3) with a springco green. Lmt enhanced carrier should help delay unlocking and be beneficial as well but they are extremely difficult to come by atm.

As a complete system the Surefire OBC would also be beneficial but like the lmt they are extremely difficult to get atm.

The Sandman S isn't a particularly high back pressure suppressor. 10.5 doesn't have that long of a dwell length but it's not quite optimized for suppressor use in terms of minimizing gas and delaying unlocking. It shouldn't be that bad though.

Are you using the .30 cal end cap or 5.56? Use the 30 if you aren't.

I have the 30 cal end cap. I’ve been looking at the veltor and will be ordering something soon. Thanks for your help!

 

[S197]

10.5” barrel (223)
Carbine length gas system
Not sure where I’m ejecting
Sandman S can

Buy an LMT enhanced carrier, they sell new for around 150.00. They do a great job at diverting gas.

Also.. after shooting are you picking up brass in front, to the side or behind you?

 

[hafejd30]

I run a bootleg carrier. 10.5” barrel. Carbine gas length. Pri gas buster. Don’t remember the buffer. Saker ASR 556

Runs excellent on position 3/4. Definitely noticeable when adjusting between the settings. But at 3 it’s a soft shooter and runs like a top

 

[Zak Smith]

Restrict gas aperture to around 0.060" and run whatever can you want. It will run great.