Best Suppressed SBR Ever????

[BufordTJustice]

Ok, shooting buddy apparently took a pic of me shooting the aforementioned upper after it "warmed up" a bit...

Attachment 54549

Excellent!

I use the same BCM foregrip and the same handguard.

[Clint]

The concepts are still the same.

Suppressors increase available gas drive.

Different models cause more or less increase, but they all do it.

There are 3 options for dealing with it.
1) Do nothing & live with faster cycling and gas blow back
2) Setup for Dedicated suppressed - runs perfectly suppressed but barely functions unsuppressed
3) Setup for Mixed Use - runs slightly fast suppressed and runs with reduced margin unsuppressed


Grant's SBR is the second variety.

The traditional way to get a small port barrel was to cut down a 16" carbine barrel.

The other way is to use an adjustable gas block or a gas block with fixed ports.

These work but are not quite the same as a small port in the barrel.


Currently, both Black River Tactical and Sionics Weapon Systems are offering small port 11.5" barrels suitable for dedicated suppressed use.

This eliminates the need to cut down longer barrels or use special gas blocks.

I was following this thread for a few years and even bought a 6920 as a base gun for a SBR build to be run suppressed and unsurpressed before the 2016 election. Original plan was to have the barrel shortened and a adjustable GB put on...probably pinned. Then add an LMT enhanced carrier and possibly the A5 system.

For numerous reasons the my project was mothballed. Fast forward to now with the new ATF comments on pistol braces along with the release of several new designs I’m considering a BCM pistol with an 11.5” upper or just the lower and proceeding with modifiing the Colt upper I have. Possibly SBRing the Colt lower later.

My question is, since there hasn’t been a post here in a year, is the secret sauce still valid? Did I miss a new product on the market?

Thanks!

[feraldog]

....My question is, since there hasn’t been a post here in a year, is the secret sauce still valid? Did I miss a new product on the market?...

introduced within the last year, here's what surefire says their new Optimized Bolt Carrier Group SF-OBC-556

"Improved cam path delays unlocking, allowing the chamber pressure to drop another 15% which permits more gasses to exit the bore"
and
"...delays unlocking of the bolt during the firing sequence, which allows expanding gases more time to exit the bore, in turn reducing back-pressure gases exiting the upper receiver group"

can anyone tell us how this BCG compares to the LMT Enhanced Carrier?

[IKnowNotEverything]

Currently running 11.5" Sionics RGP, Vltor A5H3, LMT enhanced carrier, and Rugged Surge. Cycles even Tula and locks back but just barely unsuppressed, honestly feels so slow it is offputting (almost like i could pull the trigger again before the bcg slams home).

With can the weak stuff cycles better, but the gun comes into it's own with full power 5.56, and runs remarkably smooth. The enhanced carrier definitely assists with M193 and the can combined. I have been extremely happy with my setup.

Next on the list will be a lightweight pistol build based around a 12.5 Centurion barrel and A5 system. Unsure if I will use the LMT enhanced carrier again. Will reevaluate after first rounds are downrange.

This is the first I have heard of of the Surefire BCG, hope to read more about it on these forums.

[feraldog]

...This is the first I have heard of of the Surefire BCG, hope to read more about it on these forums.

in which you might enjoy reading this interview with Jim Sullivan about his design of this new BCG - http://www.gunsandammo.com/editorial...ssembly/247565

[OldState]

The concepts are still the same.

Suppressors increase available gas drive.

Different models cause more or less increase, but they all do it.

There are 3 options for dealing with it.
1) Do nothing & live with faster cycling and gas blow back
2) Setup for Dedicated suppressed - runs perfectly suppressed but barely functions unsuppressed
3) Setup for Mixed Use - runs slightly fast suppressed and runs with reduced margin unsuppressed


Grant's SBR is the second variety.

The traditional way to get a small port barrel was to cut down a 16" carbine barrel.

The other way is to use an adjustable gas block or a gas block with fixed ports.

These work but are not quite the same as a small port in the barrel.


Currently, both Black River Tactical and Sionics Weapon Systems are offering small port 11.5" barrels suitable for dedicated suppressed use.

This eliminates the need to cut down longer barrels or use special gas blocks.

I would like to have a setup that ran well suppressed and unsuppressed. This thread was originally why I went with the Colt as a base gun so I could have the smaller mil spec gas port.

As of late 2018 what would be the current recommendation for this setup? I was thinking of going 11.5”. Should I cut the Colt barrel down or just buy one?. Is a the Colt gas port big enough to cycle an 11.5” setup? Is the adjustable gas block still a good option?

Thanks everyone for the help.

[Lawnchair 04]

I wouldn’t bother with cutting the colt barrel down, save it for another inevitable build. As mentioned above both Sionics and BRT offer properly ported 11.5 barrels than run suppressed and unsupressed just fine. Personally I just test fired my Sionics RGP last week and it was flawless both suppressed and not with IMI M193.

My build consisted of the RGP barrel, Surefire Socom 762 mini, geissele gas block, LMT enhanced BCG group, Vltor A5h3 with Springco Green. I wanted to tame the gas a bit but not sacrifice reliability nor have to mess with adjustable gas blocks.

Next up is a pistol build with either the BRT suppressor gas drive barrel or the Sionics ERGP barrel to really cut out the gas. I won’t expect it to run without the suppressor though.

[OldState]

I wouldn’t bother with cutting the colt barrel down, save it for another inevitable build. As mentioned above both Sionics and BRT offer properly ported 11.5 barrels than run suppressed and unsupressed just fine. Personally I just test fired my Sionics RGP last week and it was flawless both suppressed and not with IMI M193.

My build consisted of the RGP barrel, Surefire Socom 762 mini, geissele gas block, LMT enhanced BCG group, Vltor A5h3 with Springco Green. I wanted to tame the gas a bit but not sacrifice reliability nor have to mess with adjustable gas blocks.

Next up is a pistol build with either the BRT suppressor gas drive barrel or the Sionics ERGP barrel to really cut out the gas. I won’t expect it to run without the suppressor though.

So no offending gas blowback and reliable cycling non suppressed with all ammo on that setup? The one thing that had me a little worried about going with the Colt barrel is that my 16” 6920 doesn’t reliably cycle weak ammo (brown bear) in the cold with the stock H1 buffer.

The release of the SBA3 brace has made me consider starting this as a pistol on a new receiver and SBRing the Colt when I get the suppressor.

[Todd.K]

I have not played with the LMT enhanced BCG yet, never seem to have the money, time, and interest come together to test it out.

That said I am quite firmly in the suppressed only camp (or Switchblock) and that is where I recommend people start. For me the reason I got an SBR was to have a reasonable length with suppressor, so dedicated suppressed doesn't feel like a limitation to me.

[Lawnchair 04]

No offending gas and no issues running suppressed/unsupressed with IMI m193 I didn’t run any other ammo through it