• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Need a buffer system for suppressed 11.5 SBR

nikdanja

Private
Full Member
Minuteman
Apr 6, 2014
329
35
Warrenton Virginia
I was looking at the VLTOR system but they are sold out everywhere. My rifle is extremely over gassed and I need a system that works. Looking to change the buffer and spring.

SBR 11.5 223
Sandman S
Regular carbine buffer/spring in the gun currently.
 
  • Like
Reactions: Rockyp2013
9mm buffer and a standard spring. Mine runs all day like that. Suppressed and un-suppressed. Cheap and easy.
 
Sprinco blue spring with h2 or h3 would help for now. Or a geissele spring and same 2 or 3. Adjustable gas block is ideal, but you will still want to use a heavier buffer at a minimum with it.
 
Adj block.

Sign up for alerts for A5

Look at the builds member @MSTN does with short barrels.
He isnt the only top end builder around, and has a lot of experience building reliable hard use rigs and over many years, I have appreciated his take on things.
I have used his advise and am super happy with the results.

He posts pics and parts details in the AR15 pic thread pretty regularly.
 
  • Like
Reactions: Bryan W M
I use an A5 on both my AR’s. If you can find it in stock, it’s the way to go. But, I still had gas in my face while suppressed.


These gas tubes have been the best upgrade to my AR I’ve ever had. I use the suppressor only one, and it has smoothed out my SBR, even better than my SR15 16”.
 
JP silent buffer system.

Also, look at getting an adjustable gas block. Probably dove most of your issues with that.
 
I was looking at the VLTOR system but they are sold out everywhere. My rifle is extremely over gassed and I need a system that works. Looking to change the buffer and spring.

SBR 11.5 223
Sandman S
Regular carbine buffer/spring in the gun currently.

H3 or 9mm buffer with current spring is big improvement.
H3 or 9mm buffer & change out your buffer spring to “Orange” Springco has 99+% chance of solving issue.

H3 w/standard spring on 10.5 RRA w/SAS can and same buffer / spring with DD 10.3 w/TDS can keeps gas to a minimum.

VLTOR is nice but not “needed” to solve current issue.
 
Sprinco blue spring with h2 or h3 would help for now. Or a geissele spring and same 2 or 3. Adjustable gas block is ideal, but you will still want to use a heavier buffer at a minimum with it.
Yes

I was looking at the VLTOR system but they are sold out everywhere. My rifle is extremely over gassed and I need a system that works. Looking to change the buffer and spring.

SBR 11.5 223
Sandman S
Regular carbine buffer/spring in the gun currently.
Put H2 in and you'll be fine. I have H2 in my 10.3/Surefire RC2 which has 0.72" has port.


Do you know your gas port size?
 
I run the jp scs setup on my lmt. I’d put an adjustable gas block if you have the chance.
 
I run a factory BCM 11.5 (BCM lower also) with an A5H4 and it will run un-suppressed with the weakest of ammo. No problems ever.
 
  • Like
Reactions: 92G
I was looking at the VLTOR system but they are sold out everywhere. My rifle is extremely over gassed and I need a system that works. Looking to change the buffer and spring.

SBR 11.5 223
Sandman S
Regular carbine buffer/spring in the gun currently.



The A5 is in stock in multiple places, I really like these guys though.
https://www.rooftopdefense.com/product/vltor-a5-buffer/

https://www.rooftopdefense.com/product/vltor-re-a5-receiver-extension-buffer-tube/

I'd go A5 H2 or H3 with springco green.

I'd also go with an adjustable gas block or if that doesn't interest you get a brt eztune gas tube.

https://blackrivertactical.com/WP/BRT-EZTUNE-Gas-Tube-Configurable-Midlength-p103167236
 
Get an adjustable/tuneable gas block and run standard parts. No need for special buffers or springs. Tune it to lock back without the silencer and it will be perfect with. Or if you run a silencer all the time, tune it for that.

It reduces the amount of gas in your face, reduces felt recoil and keeps the gun cleaner.
 
If your gun is truly over gassed I look into getting a new barrel from a manufacturer that actually measures gas port size. Adjustable gas blocks are problematic and are generally not as durable. Going with a heavier buffer or an A5 system is your best option if you don’t want to buy a new barrel.
 
I use the TUBB carrier weight system and the flatwire spring in my finicky 300 blk guns and they work awesone, its adjustable to several different weights. and the sping has been great, even on its own
 
Superlative AGB with a JP SCS. Use this setup in my 10.5 suppressed with a Sandman S. Smoooooth
 
“My car is stuck at full throttle, help me upgrade to bigger brakes to slow it down.” 🙄

If it’s severely overgassed, the obvious answer is to fix the gas issue. It doesn’t matter what method you choose, as long as the gas is restricted to the appropriate level.

The solution can be anything from a new barrel (not what I’d recommend), to an adjustable gas block, restrictive bushings in a gas block, tuned or adjustable gas tubes, or even an adjustable gas key. Personally I’d suggest a good adjustable gas block like the Seekins model and don’t fiddle with it once it’s set, or have someone capable make a restriction bushing for your current gas block. Either way is the same effect as a barrel that’s ported right to start with.
 
I did the Geissele buffer and spring with a piston upper but it works with an adjustable gas block with another upper i have. Both run the silenced at all times.
 
If your only problem is over gassed,forget all the crap and get a Bootleg gas adjustable BCG. Can be adjusted with a spent round on the fly without disassembly. 4 position selector for suppressed to unsupressed and handles 300aac no problem. Oh and it works great with the JP SCS.
 
As some of the others have said, a Bootleg adjustable BCG and a tubbs spring should solve your problem. Bootleg has them in stock, it’s a very effective BCG!
 
@nikdanja
A5 RE are available

I like the vltor a5 system but as others mention it’s not going to fix your overgassed problem. dwell time is everything. I personally don’t bother with anything DI unless I can get a rifle length gas system. My 16” Reece rifles now use criterion barrel w rifle gas for this reason.

the best fix for your 11.5 is going to be a mid length gas (not carbine) and either an adjustable gas block or something like the YHM suppressor block which will cut down on gas. I personally do not like AGB as they all seem to seize over time and I don’t like the idea of a possible failure point in gas system.

the following are all band-aid solutions to delay unlock time but none of them actually increase the dwell time, which is the ultimate solution:
-heavy buffers, A5 RE to allow rifle springs, adjustable BCG’s such as bootleg.

another solution is to use .30 cal cans on .223 auto loader rifle. The overbore suppressor will provide much less port pop and sometimes sound better for this reason. The OSS helix design will also run smoothly on your shorty.

if you decide to go with an A5 system start with an A5H3. my RRA 16” mid length will cycle the A5H4 on a cold day with weak ammo. Your 11.5 will still be over gassed even with a heavy A5 buffer.

good luck
 
Last edited:
I personally don’t bother with anything DI unless I can get a rifle length gas system. My 16” Reece rifles now use criterion barrel w rifle gas for this reason.
I'm almost in that same boat. Most people on this forum insist you can't feel the difference between mid and rifle, and they're wrong or they OD'd on tetracaine. I've got a 14.8" rlgs gun up and running and the next project is a 17" rifle +1".
I personally do not like AGB as they all seem to seize over time and I don’t like the idea of a possible failure point in gas system.
In what ways have you seen AGB's fail?
 
I'm almost in that same boat. Most people on this forum insist you can't feel the difference between mid and rifle, and they're wrong or they OD'd on tetracaine. I've got a 14.8" rlgs gun up and running and the next project is a 17" rifle +1".

In what ways have you seen AGB's fail?

never seen an AGB fail but I’ve only build 2 rifles with them. Both are LR-308‘s with SLR sentry AGB. They seem to seize and lose adjustability unless the user intentionally cycles the detent screw after each use to help clear out carbon. This is not a knock on SLR but rather to me it speaks to the imperfect nature of AGB if even SLR can’t do it perfectly.
 
  • Like
Reactions: Orion1957
never seen an AGB fail but I’ve only build 2 rifles with them. Both are LR-308‘s with SLR sentry AGB. They seem to seize and lose adjustability unless the user intentionally cycles the detent screw after each use to help clear out carbon. This is not a knock on SLR but rather to me it speaks to the imperfect nature of AGB if even SLR can’t do it perfectly.
Then they didn't fail, they just held the adjustment permanently which is the default mode of a non adjustable block. Sounds great.
The key is to buy a cheaper one like a Seekins so you're not mad when it locks up.
 
  • Like
Reactions: Yondering
I was looking at the VLTOR system but they are sold out everywhere. My rifle is extremely over gassed and I need a system that works. Looking to change the buffer and spring.

SBR 11.5 223
Sandman S
Regular carbine buffer/spring in the gun currently.
I use a David Tubbs buffer spring and h3 buffer with a gemtech bolt carrier and it will smooth everything out for you.
 
If your gun is truly over gassed I look into getting a new barrel from a manufacturer that actually measures gas port size. Adjustable gas blocks are problematic and are generally not as durable. Going with a heavier buffer or an A5 system is your best option if you don’t want to buy a new barrel.
I run them on everything. Never had a problem with them changing adjustments or coming loose.

I run a lightweight bolt and lightweight buffer (1.5 ounces) on my 11.5”. It is as soft shooting as any AR I have ever shot. It has been 100% reliable in a few thousand rounds.
 
  • Like
Reactions: Yondering
Over gassed with or without the can or both?

A5's are out there, if you look hard enough. I bought my last 2 A5's from Primary Arms, not sure if they still have them in stock or not.
 
@nikdanja
A5 RE are available

I like the vltor a5 system but as others mention it’s not going to fix your overgassed problem. dwell time is everything. I personally don’t bother with anything DI unless I can get a rifle length gas system. My 16” Reece rifles now use criterion barrel w rifle gas for this reason.

the best fix for your 11.5 is going to be a mid length gas (not carbine) and either an adjustable gas block or something like the YHM suppressor block which will cut down on gas. I personally do not like AGB as they all seem to seize over time and I don’t like the idea of a possible failure point in gas system.

the following are all band-aid solutions to delay unlock time but none of them actually increase the dwell time, which is the ultimate solution:
-heavy buffers, A5 RE to allow rifle springs, adjustable BCG’s such as bootleg.

another solution is to use .30 cal cans on .223 auto loader rifle. The overbore suppressor will provide much less port pop and sometimes sound better for this reason. The OSS helix design will also run smoothly on your shorty.

if you decide to go with an A5 system start with an A5H3. my RRA 16” mid length will cycle the A5H4 on a cold day with weak ammo. Your 11.5 will still be over gassed even with a heavy A5 buffer.

good luck
how does midgas on a 11.5" barrel even approach correct dwell timing, same with rifle gas on your 16" Critieron; those 7 inches past the gas port are critical.
 
  • Like
Reactions: 92G
those 7 inches past the gas port are critical.
dsmGaKWMeHXe9QuJtq_ys30PNfTGnMsRuHuo_MUzGCg.jpg
 
  • Like
Reactions: Dolomite_Supafly
well, i guess one could simply open up the barrel's gas port as Colt tried by chopping 20" barrels to 16" with their early Dissapator during Vietnam, it failed miserably on auto due to timing and dwell issues. Remember those?
DPMS tried it in the late 1990s, it failed as well. Same with Fulton Armory.
Not until Bushmaster refined the concept in the late 1990s by placing a shaved gas block under A2 handguards (carbine gas port) while using another A2 sight out front did the concept proove reliable on semi or FA. and today.... using FN chf barrels, PSA is offering both carbine and midgas Dissapator uppers that run with the best.
more recent tests from Dr. Phil Dater explaines the physics side and how to avoid serious over gassing on shorter systems both with, and without, suppression. it's a great read.
 
well, i guess one could simply open up the barrel's gas port as Colt tried by chopping 20" barrels to 16" with their early Dissapator during Vietnam, it failed miserably on auto due to timing and dwell issues. Remember those?
DPMS tried it in the late 1990s, it failed as well. Same with Fulton Armory.
Not until Bushmaster refined the concept in the late 1990s by placing a shaved gas block under A2 handguards (carbine gas port) while using another A2 sight out front did the concept proove reliable on semi or FA. and today.... using FN chf barrels, PSA is offering both carbine and midgas Dissapator uppers that run with the best.
more recent tests from Dr. Phil Dater explaines the physics side and how to avoid serious over gassing on shorter systems both with, and without, suppression. it's a great read.
That's nice. 4 cylinder engines used to top out at 140hp too. Things change, longer gas systems are more viable than they used to be.
 
how does midgas on a 11.5" barrel even approach correct dwell timing, same with rifle gas on your 16" Critieron; those 7 inches past the gas port are critical.
IMHO- I would not give much credibility to someone who says “dwell time is everything” (it’s not), the same as I would treat someone who says a long gas system in a short barrel doesn’t work, or is the only way to go, or whatever.

There are multiple important aspects of the DI gas and recoil system that have to balance each other, and no one part is “everything” or the only detail to focus on. The truth is that as long as you balance the system, there are many different ways to make it run right and not just one right answer.

Short dwell time for example can be balanced by a larger gas port and/or a lighter spring or buffer. Of course there are extremes beyond which it’s unrealistic to try to balance the system, like if it’s extremely overgassed (per the OP), hence the recommendations for him to fix that issue first before wasting money on buffers.
 
  • Like
Reactions: TonyTheTiger
how does midgas on a 11.5" barrel even approach correct dwell timing, same with rifle gas on your 16" Critieron; those 7 inches past the gas port are critical.

16” with rifle gas system would have only 4” between gas port and muzzle.

similarly, a mid gas on 11.5” is something I’d probably run as a dedicated suppressed rifle.

for my DI guns I typically use direct thread suppressors and the gun is tuned, then left as is. my piston setups seem far more suited for QD suppressor as they’ll run fine in both conditions. This is just my system…nothing particularly intelligent about it.



also in my post above I noticed I did not use dwell time term correctly. What I meant to describe is the lock time…the key to running a suppressor on a DI gun is to delay the unlocking as long as possible. If there was a way to store the kinetic energy for another 100 ms that would be tremendous and essentially remove all the port pop.
 
  • Like
Reactions: Yondering
“My car is stuck at full throttle, help me upgrade to bigger brakes to slow it down.” 🙄

If it’s severely overgassed, the obvious answer is to fix the gas issue. It doesn’t matter what method you choose, as long as the gas is restricted to the appropriate level.

The solution can be anything from a new barrel (not what I’d recommend), to an adjustable gas block, restrictive bushings in a gas block, tuned or adjustable gas tubes, or even an adjustable gas key. Personally I’d suggest a good adjustable gas block like the Seekins model and don’t fiddle with it once it’s set, or have someone capable make a restriction bushing for your current gas block. Either way is the same effect as a barrel that’s ported right to start with.

I drill the port in the gas block then tap it for a setscrew. Then I drill the correct port size in the set screw and screw it up into the gas block. Works great, will not fall out of adjustment and it can be done to any gas block.

I do this to a LOT of short barrels with a factory FSB. It is easy to do and retains the original FSB. And no one is the wiser. I have an 11.5" gun that feels about like a typical 16" gun with the silencer on and feels like a 20" without the silencer. Every person who has shot it was surprised at how smooth it felt. From the factory this barrel was pretty close to where it needed to be. It still needed ~.010" smaller to settle it down.