Suppressor Back Pressure

[mic2377]

Having shot thousands upon thousands of rounds through suppressed weapons, it is important to understand that even with a low back pressure suppressor and clean-burning propellant/load, everything will be dirtier no matter what you do.

Most of the time it does not make any difference in function. AR's are quite tolerant of fouling as long as they are lubed frequently.

A short gas system in an over gassed weapon will indeed blow a fair amount of fouling back towards the shooter. A pistol caliber AR in 9/10 mm will be less so. One of the best setups for a suppressed AR is a 18" rifle gas barrel, IE the MK12 SPR. The longer gas system makes it more tolerant of back pressure and softer shooting.

If you want to reduce fouling I would also consider an overbore suppressor (IE 46 Cal for a 357 caliber). This will make suppression less effective though. The welcome side effect is you can use it on more weapons.

 

[troupe]

maybe look into the powder you are burning lots of answers there. are you shooting suppressed?

Yes it is suppressed.

 

[jpjulian]

April 2022 I was firing an SBR in .300 Blackout that was suppressed at a range in Georgia. Gassy doesn't describe it. I wear glasses yet took gas to my right eye that caused vision issues for about a year. As an Illinois resident I can't own a suppressor, but should that change, how gassy it would be on my firearm is the first question I'd ask as well as attempt a try before I buy. That gas in the face was very unpleasant.

 

[dellet]

In general, the fastest powder that will style the action, will be the cleanest.

Bullet weight, barrel length, baffle construction all come into play, but generally speaking the faster powder loads will require less powder, develop more pressure so burn a higher percentage of the powder, therefore cleaner with less smoke, halve lower muzzle pressure so less sound and flash to mitigate. Less left over unburned powder to get into the fire control group.

It’s tougher with a blow back design, but the longer the action stays closed, the quieter to the shooter it will be and the less smoke in your face. It’s easy with a gas gun, the longer the gas tube, the longer the bolt stays closed. With blow back it’s springs and buffer and carrier weight.

Shooting suppressed priorities can change the three basic qualities in shooting. Quiet, clean, accurate. Generally one of those suffers to get the highest performance of the others.

 

[GotRDid]

Look into the Banish 45 Titanium from Silencer Central. Switching adapter pistons allows use on multiple Pistol/PCC hosts.
I love mine!

 

[GotRDid]

Banish review:

 

[Cecil S.]

PewPew Tactical review does not mention any blow back on the CMMG 10mm. I personally would shoot it a as lightly lubed as is possible, reliable, and protective of the gun. Oil and grease gathers stuff and some remaining gas might blow it back in your face.

The CMMG delayed blowback system does not use a gas tube, so you won't be blowing gas back against the bolt and dumping it inside your receiver. With a suppressor that has ample volume and a good baffle design, you shouldn't have a minutes problem. Some low pressure gas may come back, but I have no experience with the CMMG, so I don't know.

As far as a suppressor goes, you are going to be limited to something that can handle 10mm and up and that can disassembled for cleaning.

How CMMG Radial Delay System Works

Pew Pew 10mm Review

I built a 300 SBR, and bought a 45acp straight blow back AR (that was a total disaster and returned for refund). Neither impresses me even a little bit for the type shooting I do, and was therefore a waste of time and money. But I have to admit that the 45 with a Hybrid 46 was amazingly quiet.

So good luck.

Hello Knotwild , Thank you for your reply. I am leaning towards the Rugged Obsidian 45 or the OSS RAD45. I feel you are correct about the gas and "Delayed Blow Back" system.

 

[Gabe22BR]

I own the obsidian 45, I really like it !!
I have all the adapters, mounts, endcaps, offered for it.

Ive used it on 45acp,9mm, 22LR, so far.. and very happy with it.

 

[Cecil S.]

April 2022 I was firing an SBR in .300 Blackout that was suppressed at a range in Georgia. Gassy doesn't describe it. I wear glasses yet took gas to my right eye that caused vision issues for about a year. As an Illinois resident I can't own a suppressor, but should that change, how gassy it would be on my firearm is the first question I'd ask as well as attempt a try before I buy. That gas in the face was very unpleasant.

Hello jpjulian , DANG....sorry to hear about your experience. Hope all is well now. This is why I am doing my home work before I drop good money on this project.

 

[Cecil S.]

In general, the fastest powder that will style the action, will be the cleanest.

Bullet weight, barrel length, baffle construction all come into play, but generally speaking the faster powder loads will require less powder, develop more pressure so burn a higher percentage of the powder, therefore cleaner with less smoke, halve lower muzzle pressure so less sound and flash to mitigate. Less left over unburned powder to get into the fire control group.

It’s tougher with a blow back design, but the longer the action stays closed, the quieter to the shooter it will be and the less smoke in your face. It’s easy with a gas gun, the longer the gas tube, the longer the bolt stays closed. With blow back it’s springs and buffer and carrier weight.

Shooting suppressed priorities can change the three basic qualities in shooting. Quiet, clean, accurate. Generally one of those suffers to get the highest performance of the others.

Hello dellet, thank you for your reply it is spot on to what i have read. I have discovered the 10mm will not be the quietest even suppressed but the "can" greatly helps with recoil. I am covered in the powder area but will be uping my supply of heavier 10mm bullets.

 

[Cecil S.]

Look into the Banish 45 Titanium from Silencer Central. Switching adapter pistons allows use on multiple Pistol/PCC hosts.
I love mine!

Thanks Bro, will check this out.

 

[USMCsilver]

I've not read the whole thread, but a KAK down venting BCG will nearly fix any exhaust issues.

 

[Cecil S.]

I own the obsidian 45, I really like it !!
I have all the adapters, mounts, endcaps, offered for it.

Ive used it on 45acp,9mm, 22LR, so far.. and very happy with it.

Thanks Gabe22BR, yeah the Obsidian 45 maybe my choice. This research is very deep and alot to understand.

 

[Cecil S.]

Having shot thousands upon thousands of rounds through suppressed weapons, it is important to understand that even with a low back pressure suppressor and clean-burning propellant/load, everything will be dirtier no matter what you do.

Most of the time it does not make any difference in function. AR's are quite tolerant of fouling as long as they are lubed frequently.

A short gas system in an over gassed weapon will indeed blow a fair amount of fouling back towards the shooter. A pistol caliber AR in 9/10 mm will be less so. One of the best setups for a suppressed AR is a 18" rifle gas barrel, IE the MK12 SPR. The longer gas system makes it more tolerant of back pressure and softer shooting.

If you want to reduce fouling I would also consider an overbore suppressor (IE 46 Cal for a 357 caliber). This will make suppression less effective though. The welcome side effect is you can use it on more weapons.

Hello mic2377, thanks for your reply. your information is spot on with what i have read. For now my first choice is the Rugged Obsidian 45.

 

[spaniel]

Half a dozen AR's and three suppressors, I have to say suppressor blow-back is one of those things I worried about before I had personal experience, and once I had personal experience, decided was way overblown. Can't say I notice. I do notice that everything gets dirty, including rounds in the mag.

 

[Cecil S.]

Half a dozen AR's and three suppressors, I have to say suppressor blow-back is one of those things I worried about before I had personal experience, and once I had personal experience, decided was way overblown. Can't say I notice. I do notice that everything gets dirty, including rounds in the mag.

Hello spaniel, I hear you. But before I drop this kind of coin I want to feel like I covered my bases. I tend to be from the school of "buy once cry once" and yes I am ready to clean more then usual.

 

[woven_fire_on_fire]

Hey folks, I'm new here but this sounds like a good thread to dive in on.

I own one of the quietest silencers on the market, a Nomad L, as well as a low back pressure traditional baffle stack can or two (turbo k and rugged razor) as well as a flow through can.

I specifically built an optimized AR-15 to see how quiet that platform would get will full house 77 grain 556 ammo- 11.5 middy with h4 and LMT delayed bolt.

Long story short- it sounds about like an unsuppressed 10-22 to the ear. Maybe a bit louder. I played in bar bands for years and did other did other ignorant youthful activities and my hearing isn't ideal- well actually I hear fine but have constant ringing and loud noises make it worse.

Even the highly tuned upper with the nomad l was enough for me to hear crickets and fax machines chirping all night.

I don't think chasing DBs on an AR is worth it. I've come to love the flow through cans because the action and brass stays clean and the gun runs identical with or without the can. My tuned guns won't even cycle or lock back without the suppressor, rendering the rifle useless when it's on something else. Ask yourself if you're willing to dedicate a silencer to a single rifle. If not are you comfortable making that rifle a paperweight when the can is screwed on something else? This always bothered my OCD.

For ARs, even if it's just one shot I'm wearing ear pro unless it's a self defense situation, in which case even the loudest cans on the market are more than enough.

Now for the CMMG- I had their delayed bolt 9mm upper than I've run with an R9 and obsidian 9.

Now the obsidian is a neat little can because it's seviciable I can run it on rimfire rifles and on a 357 lever gun shooting cast lead. Pretty handy.

Because that's a blow back not a DI gun it won't really matter what can you run they'll all pretty much act the same. It'll be a bit messy but you won't have gas to the face issues like you would a rifle round. Not enough powder to matter.

Mine never ran 100% and I tripped it. After having a closet full of AR15s in various flavors (9mm Grendel, legend, 308), I've decided I like that platform in 223 with a 11-14 inch barrel, can. Flashlight, dot or lpvo, and that's enough for me.

Give me a 1911 or a bolt action for everything else.

Let me know if you've got specific Qs,

WWOF

 

[IAm_Not_Lost]

I’ve never had an issue with back pressure and think it’s overblown. Sure, if you have an over gassed gun, any suppressor will add a little extra back pressure, but folks act like they’re drowning in gas and debris. I’ve got a standard Dead Air Sandman K along with Form 1’s that all use standard baffles and have never had an issue on my AR’s.

If you’re concerned but don’t want to fork over extra money for a DIXWRX can and poor sound reduction I would just get a can that is slightly over bore, i.e. use a 30 cal can for your 223.

 

[mic2377]

Hello mic2377, thanks for your reply. your information is spot on with what i have read. For now my first choice is the Rugged Obsidian 45.

If you are curious - the majority of my suppressed shooting has been with overbore cans, primarily either a Form 1 can that is around 33 cal used on 223/308, or a 9 mm pistol can on 22 LR. My friends are more picky about using a specific 22 cal can on 223 and such, but they have never once complained about a lack of suppression with my setups. I have also experienced very few functional issues besides more frequent cleaning.

In fact I recently added a large bore can to the stable (Primal 46) because of the versatility and its magnum rifle cartridge rating. It is also perfect for 9 mm/45 pistol caliber carbines too. One downside of the Obsidian is it is basically rated for only small rifle or pistol cartridges only.

 

[akajun]

Guys used to use RTV silicone sealant on the charging handle. De-oil the CH so the sealer sticks to it, apply some kind of release agent to the upper receiver so the sealer doesn't stick to it, then fill the gap between the upper and the CH with the sealer. smooth it off so it looks nice and let it dry. I've never done that so I can't say but guys who did said it cut down on the gas to the face.

There used to be a plug you could buy that went in place of the forward assist assy. that acted as a vent, directing gas down and away. I don't know if you can still get those. I've never felt the need for one. Of course it eliminates the forward assist function.

This
Works very well
Started doing this because of shooting highpower I put my nose on the charging handle in offhand, would dry my eyes out