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CT, USA
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Posted: 7/30/2023 4:18:19 PM EDT
Hey guys. I have a BCM MK2 BFH 11.5" Carbine with a Dead Air Nomad suppressor. Im running a Geisselle super 42 H3 buffer and a Geisselle airborne charging handle. This set up is extremely over gassed and has a ton of gas hitting you in the face and throwing brass almost straight forward. I started by buying a Bootleg adjustable bolt carrier, hoping to avoid an adjustable gas block. It helped a lot and has lowered the recoil and adjusted the brass deflection. But the gas in the face is still there, much worse than I would like. What do guys suggest doing from here or is this just the way it is for a suppressed short barrel? I was thinking about removing the adjustable BCG and running a superlative arm adjustable gas block, do you think that will make a difference? Would a dedicated "gas busting" charging handle help? Seems like most people have mixed results with them.
Thanks 
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Posted: 7/30/2023 4:32:40 PM EDT
[#1]
Other than an adjustable gas block or carrier, there’s not much you can do.
I have one and it runs fine with an enhanced action spring and H2 buffer. Just shoot it… |
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Posted: 7/30/2023 4:40:00 PM EDT
[#2]
No personal experience, but BRT gas tubes get a lot of positive reviews.
https://blackrivertactical.com/WP/BRT-EZTUNE-Gas-Tube-Configurable-Carbine-p103167251 |
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FL, USA
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Posted: 7/31/2023 2:09:00 PM EDT
[#3]
https://www.riflespeed.com/
Works good but NOT cheap. |
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SC, USA
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Posted: 7/31/2023 2:32:30 PM EDT
[#4]
You can try an adjustable gas block or go with the Black River Tactical gas tube, which would be easier.
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CO, USA
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Posted: 8/1/2023 11:33:33 AM EDT
[#5]
It's definitely not "just the way it is". I have 2 11.5" ARs that I run suppressed. Neither is overly gassy. One is a faxon gunner barrel with adjustable gas block. The other is a criterion with a BRT tube. I'm one of the people that thinks the gas buster CH is over rated. I tried it, but preferred my Vltor and have the gas buster to my kid. If you're willing to try an adjustable gas block I think it would help. Some people view them as a failure point and won't use them. That's up to you. If you'd rather not, the BRT tube is a good option. You can tell them your set up, type of ammo, etc and they will send you the port size for what you're running. Same concept as the AGB, but obviously not adjustable.
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IA, USA
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Posted: 8/1/2023 11:35:34 AM EDT
[#6]
this is why piston
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CT, USA
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Posted: 8/1/2023 7:10:58 PM EDT
[#7]
Thanks for the help, guys. Honestly i have no experience with short barrels suppressed. The gas to the face is more annoying than anything, everything functions perfectly. but I'm always the guy that wants to tinker with stuff. From the research I've seen, it seems like the BCM 11-12in barrels run a larger gas port and are all super over gassed. In hindsight I probably would have gone a different direction. I was able to return the used adjustable bolt carrier and i ordered a Superlative arms adjustable gas block. I was hoping the adjustable BCG would be a simple fix, not needing any tools to adjust the gas, and having the ability to just place the factory one in if I have a problem. But it deff didn't work out.
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CO, USA
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Posted: 8/1/2023 9:57:43 PM EDT
[#8]
I've never used an adjustable BCG, so I can't say the block will necessary be better, but I do think it will help. I CAN say that there is a fix. I shoot 10.3, 11.5, 14.5 and 16" ARs suppressed and the only time gas bothered me was with the gas buster. It didn't smack me in the face with gas, but it would vent it up towards my face after strings of fire. There is a set up that will work for you. It's just a matter of finding it.et us know how the block works out. I adjusted mine (unsuppressed) to just lock back with the weakest ammo I use and then gave it one more click just in case. It works well with and without the suppressor. I've tried choking it down more to try and see the benefits of "suppressed only", but unless I just didn't go far enough, I don't see enough change to justify it.
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Posted: 8/1/2023 10:08:23 PM EDT
[#9]
Another option is the YHM restricted gas block. Port is really small so you’ll likely need to drill it but it’s steel and less than $20 shipped. I have one on the way for a 10.3” that has a huge port.
BRT gas tube is the cheapest and easiest option though. |
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CO, USA
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Posted: 8/6/2023 7:02:04 AM EDT
[#10]
Quote HistoryOriginally Posted By jhon: Another option is the YHM restricted gas block. Port is really small so you’ll likely need to drill it but it’s steel and less than $20 shipped. I have one on the way for a 10.3” that has a huge port. BRT gas tube is the cheapest and easiest option though. If the YHM block is $20, then it's quite a bit cheaper than the BRT tubes. |
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TX, USA
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Posted: 8/7/2023 12:38:10 PM EDT
[Last Edit: crosseyeshooter]
[#11]
Quote HistoryOriginally Posted By Stowe: If the YHM block is $20, then it's quite a bit cheaper than the BRT tubes. If it saves 30 minutes of aggravation pulling the muzzle device and gas block, the BRT tube is probably worth it. Here's their preset tube for suppressed-only carbine-length gas systems. For 50/50 mixed use, they have a configurable tube that costs ten bucks more ($65). If I were going to replace the gas block anyway, I'd go straight for an adjustable one like the Superlative Arms. The Bootleg BCG actually vents gas out the ejection port, increasing gas near the shooter if there's no wind to blow it away. As a left-handed AR shooter, I'm particularly sensitive to suppressor back pressure. Of the normal baffle-style suppressors I've tried on my 11.5" piston gun, the Sandman K had low enough back pressure to really eliminate gas-to-the-face, but the sound suppression sucks. I believe the Nomad is one of the highest back pressure cans. I'm starting to look at flow-through suppressors for future purchase. |
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Posted: 8/7/2023 12:56:38 PM EDT
[#12]
Quote HistoryOriginally Posted By scostu: https://www.riflespeed.com/ Works good but NOT cheap. Pretty sure you'll have to replace the handguard with a shorter one if you want to use a Riflespeed. I tried on my 11.5" BCM and I couldn't turn it. Ended up using an Aero gas block. The adjustable gas block helps but in my experience, you'll always end up with some gas to the face. |
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Posted: 8/7/2023 12:58:01 PM EDT
[#13]
Quote HistoryOriginally Posted By crosseyeshooter: If it saves 30 minutes of aggravation pulling the muzzle device and gas block, the BRT tube is probably worth it. Here's their preset tube for suppressed-only carbine-length gas systems. For 50/50 mixed use, they have a configurable tube that costs ten bucks more ($65). If I were going to replace the gas block anyway, I'd go straight for an adjustable one like the Superlative Arms. The Bootleg BCG actually vents gas out the ejection port, increasing gas near the shooter if there's no wind to blow it away. As a left-handed AR shooter, I'm particularly sensitive to suppressor back pressure. Of the normal baffle-style suppressors I've tried on my 11.5" piston gun, the Sandman K had low enough back pressure to really eliminate gas-to-the-face, but the sound suppression sucks. I believe the Nomad is one of the highest back pressure cans. I'm starting to look at flow-through suppressors for future purchase. Quote HistoryOriginally Posted By crosseyeshooter: Originally Posted By Stowe: If the YHM block is $20, then it's quite a bit cheaper than the BRT tubes. If it saves 30 minutes of aggravation pulling the muzzle device and gas block, the BRT tube is probably worth it. Here's their preset tube for suppressed-only carbine-length gas systems. For 50/50 mixed use, they have a configurable tube that costs ten bucks more ($65). If I were going to replace the gas block anyway, I'd go straight for an adjustable one like the Superlative Arms. The Bootleg BCG actually vents gas out the ejection port, increasing gas near the shooter if there's no wind to blow it away. As a left-handed AR shooter, I'm particularly sensitive to suppressor back pressure. Of the normal baffle-style suppressors I've tried on my 11.5" piston gun, the Sandman K had low enough back pressure to really eliminate gas-to-the-face, but the sound suppression sucks. I believe the Nomad is one of the highest back pressure cans. I'm starting to look at flow-through suppressors for future purchase. Those are interesting, never tried them before |
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CO, USA
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Posted: 8/7/2023 5:41:00 PM EDT
[#14]
Quote HistoryOriginally Posted By Switchback_Arms: Those are interesting, never tried them before I have 3 BRT tubes. They work. They shouldn't have to. barrel makers should get their heads out of their asses and port shit right, but if you need one, they're effective and an easy swap. |
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MN, USA
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Posted: 8/7/2023 6:34:53 PM EDT
[#15]
Quote HistoryOriginally Posted By Stowe: I have 3 BRT tubes. They work. They shouldn't have to. barrel makers should get their heads out of their asses and port shit right, but if you need one, they're effective and an easy swap. Port shit right for what? Same dudes buy the same barrels that some suppress and don't. There is no one size fits all. |
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Posted: 8/8/2023 1:14:16 PM EDT
[#16]
The Bootleg adj carrier works by venting the excess gas out of the ejection port. It does nothing to limit the amount of gas being introduced to the gas key. They are great at tuning function (as you mention in your OP) but they have their limitations, namely they increase at-ear dB significantly when shooting suppressed.
An adj gas block works to restrict the amount of gas being introduced to the action. The Superlative also has a bleed off mode that vents excess gas, but in doing so it still limits how much gas goes to the gas key. If "gas face" is your main concern, get an adj gas block. |
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CO, USA
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Posted: 8/8/2023 4:21:54 PM EDT
[#17]
Quote HistoryOriginally Posted By s4s4u: Port shit right for what? Same dudes buy the same barrels that some suppress and don't. There is no one size fits all. Obviously they can't make it ideal for everyone, and some companies ARE doing things right. You don't need a "suppressed only" gas port to run suppressed, but something smaller than a sewer pipe would be nice. |
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MN, USA
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Posted: 8/8/2023 5:03:15 PM EDT
[#18]
Quote HistoryOriginally Posted By Stowe: Obviously they can't make it ideal for everyone, and some companies ARE doing things right. You don't need a "suppressed only" gas port to run suppressed, but something smaller than a sewer pipe would be nice. And I have had to open up the gas ports on the last two barrels I have built out. Again, right for whom? I prefer over-gassed to under-gassed, it is easier to deal with. |
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CT, USA
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Posted: 8/17/2023 4:35:29 PM EDT
[#19]
So I ended up replacing the gas block with a Superlative Arms adjustable. It made a pretty big difference. The little bit of gas coming back is not a problem. With sunglasses on, it’s not noticeable at all.
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Posted: 8/19/2023 6:27:45 AM EDT
[#20]
I thought the BCM uppers were supposed to be undergassed to the lint they have trouble running steel?
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CT, USA
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Posted: 8/19/2023 6:31:48 AM EDT
[Last Edit: 3rdgens]
[#21]
Mine was deff not under gassed. With an h3 buffer and a dead air nomad. I was throwing brass almost straight forward. Heaviest recoiling 5.56 I had ever shot.
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Posted: 8/19/2023 7:13:25 AM EDT
[#22]
Quote HistoryOriginally Posted By triburst1: I thought the BCM uppers were supposed to be undergassed to the lint they have trouble running steel? There’s always the possibility BCM changed specs due to customer feedback/complaints. More than a few companies have gone back and forth with the gas port size topic. |
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Posted: 8/19/2023 7:27:06 AM EDT
[#23]
Quote HistoryOriginally Posted By triburst1: I thought the BCM uppers were supposed to be undergassed to the lint they have trouble running steel? My 14.5" BCM carbine is borderline under-gassed. It will shoot steel case, but eject it at nearly 5 o'clock. My 11.5" BCM is a little over-gassed. |
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CO, USA
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Posted: 8/19/2023 1:26:19 PM EDT
[#24]
Quote HistoryOriginally Posted By 3rdgens: So I ended up replacing the gas block with a Superlative Arms adjustable. It made a pretty big difference. The little bit of gas coming back is not a problem. With sunglasses on, it’s not noticeable at all. Nice. When you feel like messing with it more I'd suggest trying a std spring and regular carbine buffer and choking the gas down even more to compensate. It may not make a dramatic difference, but it should be noticeable and less reciprocating mass will make for a flatter shooting gun. |
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CT, USA
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Posted: 8/20/2023 9:02:37 AM EDT
[#25]
Quote HistoryOriginally Posted By Stowe: Nice. When you feel like messing with it more I'd suggest trying a std spring and regular carbine buffer and choking the gas down even more to compensate. It may not make a dramatic difference, but it should be noticeable and less reciprocating mass will make for a flatter shooting gun. I know I was so mad, I run a H1 on my DMR set up and a H2 on my wife’s rifle. I easily could have brought them to try, just didn’t think too. |
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MO, USA
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Posted: 8/26/2023 5:17:31 PM EDT
[Last Edit: Joedirt199]
[#26]
I put vented set screws in my gasblocks with a .049" gasport. It has been running all my mid length gas systems and have H buffers with flat wire springs. I ordered some aluminum buffer weights as I need to drop the weight on my WOA 18" with intermediate gas before opening up the gas port.
You tap the hole in the gas block and run a 10-32 stainless steel vented setscrew up in it to reduce the gasport. BRT used to do this but switched to their money making gas tubes. It is not a hard job to tap the hole since it is already the right size for the tap. There was a thread on here with pictures on how to do it. I left my vented setscrews at 1/8" and they clear the barrel after tapping as deep as possible. I have a mix of YHM Turbo Ks and Turbo 3s and BCM barrels. |
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TX, USA
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Posted: 9/6/2023 7:00:44 AM EDT
[#27]
Quote HistoryOriginally Posted By Stowe: Nice. When you feel like messing with it more I'd suggest trying a std spring and regular carbine buffer and choking the gas down even more to compensate. It may not make a dramatic difference, but it should be noticeable and less reciprocating mass will make for a flatter shooting gun. I am also a big advocate of standard spring and 3 oz buffer with the adjustable gas block. Don't add "one more click" for reliability. Stop when the rifle runs 100% with your weakest ammo. I also don't like the vent setting on Superlative gas blocks. I get better results going with the restriction only settings. |
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CT, USA
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Posted: 9/6/2023 9:12:50 AM EDT
[Last Edit: 3rdgens]
[#28]
I’ll have to give the lighter buffer and the restriction mode a try. I have no free time to shoot this time of year. I adjusted it still a little over gassed and put 300 rounds through it. It’s a HD set up, I’m not looking for the lightest shooting gun I can, but I’d like to squeeze a little more out of it. When work calms down I’ll get a chance to screw with it
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TX, USA
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Posted: 9/8/2023 12:11:03 PM EDT
[#29]
if you bought this upper for a serious use / duty / HD application, don't dick around with hobby grade adjustable gas blocks & BCG's. just sell the upper and get something gassed more appropriately like a geissele, DD, or sionics.
tinkering will waste your money and reduce reliability. |
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IL, USA
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Posted: 9/8/2023 12:27:27 PM EDT
[#30]
Quote HistoryOriginally Posted By s4s4u: Port shit right for what? Same dudes buy the same barrels that some suppress and don't. There is no one size fits all. Exactly... Some folks only shoot legit 5.56 while suppressed. Some folks only shoot the cheap steel Wolf .223 without a can. Some folks shoot both, and everything in between. |
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Posted: 9/8/2023 1:06:14 PM EDT
[#31]
Quote HistoryOriginally Posted By Infamous: if you bought this upper for a serious use / duty / HD application, don't dick around with hobby grade adjustable gas blocks & BCG's. just sell the upper and get something gassed more appropriately like a geissele, DD, or sionics. tinkering will waste your money and reduce reliability. This is exactly why I’ve been looking for an 11.5” upper that will run reliably with or without a can with a standard gas block. |
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TX, USA
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Posted: 12/20/2023 7:21:12 PM EDT
[#32]
Quote HistoryOriginally Posted By DrRockso: this is why piston No offense but this is the most ill informed comment I've seen in awhile. The excess gas pressure is unlocking the bolt and coming down the barrel into the upper, lower, magazine, everywhere. You have to restrict the bolt from unlocking until the majority of the gas has been pushed out of the business end of the barrel. This can be achieved by the ways people have already mentioned above. Alot of people think that a piston gun would automatically solve the "gas to the face" issues but that couldn't be further from the truth (as the gas is coming down the barrel twards the shooter, not the gas tube). Long story short, your BCG is unlocking early. It's that simple. Get a .62 BRT tube and run it with a H3. By restricting the gas at the gas port with the BRT tube less will be flowing down the gas tube and thus it will take longer for the bolt to unlock (which is exactly what want). When the bolt stays locked the gas is forced out the front of the barrel. If you have a magical piston gun, and your BCG unlocks too soon, guess what that gas is coming at you just the same way it is on a DI gun. No difference.... |
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VA, USA
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Posted: 12/21/2023 11:40:56 AM EDT
[#33]
'Gas to the face'
Does this mean you see and smell the smoke after a shot, which is normal, or that you actually feel a strong puff of pressure, which would be abnormal? If you are getting that blast, I think the restricting gas tube is the easiest, quickest and cheapest fix. I would definitely do something about it now because you could get hurt continuing to shoot it. The first time I fired my new AR pistol, I noted more exhaust smoke at the rear of the receiver than I was used-to but it never struck me as a problem. I think maybe the pistols need more gas pressure than carbines. |
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Posted: 12/25/2023 11:07:57 AM EDT
[#34]
Quote HistoryOriginally Posted By FedDC: Other than an adjustable gas block or carrier, there’s not much you can do. I have one and it runs fine with an enhanced action spring and H2 buffer. Just shoot it… i went with the gieselle h2 spring and buffer and run a sandman S. rifle runs great and is pleasent to shoot. |
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