AR for use with suppressor

[Robinson]

Okay so I have pretty much decided to just go with a 16" lightweight carbine and have a suppressor mount installed. I know it will be front-heavy, but it will also suppress nicely.

My question is, how much does the gas system matter for suppressor use? I've read that a mid length gas system will be better all around and especially for use with a suppressor. I'd like to hear opinions on that from members here if you don't mind.

A was looking at a Colt 16" M4 EPR today but the carbine length gas system gave me pause. I think Colt's 6960 uses a mid length gas system?

Since I dropped the idea of a 14.5" barrel I will probably purchase a complete carbine. The Colt Trooper 6960 and the BCM Recce 16 LW are what I am looking at so far. Any opinions on those rifles? A lightweight carbine sounds better for use with a suppressor, but I do wonder if the balance front to back will actually be better with a standard weight carbine.

[WobblyPossum]

The Colt CR6960 is the CCU Carbine except with an A2 pistol grip and M4 buttstock instead of the Magpul parts the CCU had. It still has the mid-length gas system. It also uses a lighter weight barrel than the typical government profile barrel in a 6920. To answer your primary question, a longer gas system should make shooting suppressed more pleasant because it would decrease the amount of gas you’d be getting in your face compared to a shorter gas system. A carbine gas system already increases wear and tear on the gun compared to a longer one just due to how much more gas is being pushed through the gas tube into the action. Adding a suppressor generally increases that amount of gas into the action. A flow through suppressor would help mitigate that.

I’m a big fan of the BCM lightweight profile barrels and, all things being equal, would take a lightweight barrel over a government or other heavier profile barrel. The AR I put together for my girlfriend uses a BCM ELW-F 14.5” barrel with the original magnesium alloy KMR rail. The only 16” AR I currently have has an ELW 16” BCM barrel and MCMR rail. The balance with a suppressor is something only you can decide for yourself but there are some general principles about leverage that apply. The farther out from your core you hang an extra 8-16 oz you have to hold up, the heavier it will feel. Put the same suppressor on a 16” government profile gun and a 11.5” government profile gun and it’ll feel lighter on the shorter one. If you have a chance to try out someone else’s lightweight, suppressed 16” gun, that would get you better info than anything anyone could tell you about it, especially if you could compare it to a similar gun but with a heavier barrel. There’s also less of a reason to buy a full-size suppressor if it’s going on a 16” gun. Most K cans should be able to drop the decibel level below 140 on a 16” gun. A shorter, lighter suppressor will make a difference in balance and handling. I still wouldn’t shoot a 16” 5.56 rifle without ear pro, but you’d be adding additional weight and length for diminishing returns in sound reduction by buying a larger suppressor.

[Wake27]

Okay so I have pretty much decided to just go with a 16" lightweight carbine and have a suppressor mount installed. I know it will be front-heavy, but it will also suppress nicely.

My question is, how much does the gas system matter for suppressor use? I've read that a mid length gas system will be better all around and especially for use with a suppressor. I'd like to hear opinions on that from members here if you don't mind.

A was looking at a Colt 16" M4 EPR today but the carbine length gas system gave me pause. I think Colt's 6960 uses a mid length gas system?

Since I dropped the idea of a 14.5" barrel I will probably purchase a complete carbine. The Colt Trooper 6960 and the BCM Recce 16 LW are what I am looking at so far. Any opinions on those rifles? A lightweight carbine sounds better for use with a suppressor, but I do wonder if the balance front to back will actually be better with a standard weight carbine.

I'm a bit confused by what you consider standard weight vs light weight for the rifle. All other factors being equal, midlength will be better suppressed, but it doesn't seem that those other factors will be equal. What suppressor are you going to use? That and the gas port on the barrel itself are probably the two biggest determining factors for gas blow back.

FWIW, you likely couldn't pay me to use a 16" government profile barrel with a suppressor, regardless of carbine vs mid. Where did you work through the thought process of 14.5 vs 16?

[JSGlock34]

I have run my 10.3" Geissele URG almost entirely suppressed (with an AAC M4-2000) - and it is quite reliable. I think the suppressed shorties are simultaneously on the rougher end of the reliability envelope yet one of the more thoroughly tested and vetted setups over the past 20 years. Still, I suspect that mid-length gas is easier on the gun over the long term. I'd certainly go with mid-length over carbine gas with a 16" gun.

But I think the far more important decision is the can. Were I investing in a suppressor today, I would prioritize one of the flow-through designs. And on a 16" gun I'd look for a 'K' or 'Mini' model.

[Robinson]

I'm a bit confused by what you consider standard weight vs light weight for the rifle. All other factors being equal, midlength will be better suppressed, but it doesn't seem that those other factors will be equal. What suppressor are you going to use? That and the gas port on the barrel itself are probably the two biggest determining factors for gas blow back.

FWIW, you likely couldn't pay me to use a 16" government profile barrel with a suppressor, regardless of carbine vs mid. Where did you work through the thought process of 14.5 vs 16?

I'm not entirely dead set against 14.5" guns. I would need to buy the complete upper separately and send it away to have my suppressor mount permanently installed. Buying a 16" gun avoids that extra step since a local gunsmith can do a normal install.

The next reason is I already have damaged hearing and a 16" gun will be a little quieter than a 14.5" gun -- I'm not sure how much.

My suppressor is a SilencerCo Omega 300. SilencerCo rates it at 130.1 dB for 5.56, but I don't know what barrel length they used to determine that.

As for weight, I am comparing a BCM Recce 16 LW at 5.8 lbs vs a Colt M4 EPR 16 at 6.5 lbs. If the Colt 6960 Trooper uses a lighter weight barrel (as WobblyPossum posted) then it might be closer to the Recce LW in weight but I don't know.

[HCM]

I'm not entirely dead set against 14.5" guns. I would need to buy the complete upper separately and send it away to have my suppressor mount permanently installed. Buying a 16" gun avoids that extra step since a local gunsmith can do a normal install.

The next reason is I already have damaged hearing and a 16" gun will be a little quieter than a 14.5" gun -- I'm not sure how much.

My suppressor is a SilencerCo Omega 300. SilencerCo rates it at 130.1 dB for 5.56, but I don't know what barrel length they used to determine that.

As for weight, I am comparing a BCM Recce 16 LW at 5.8 lbs vs a Colt M4 EPR 16 at 6.5 lbs. If the Colt 6960 Trooper uses a lighter weight barrel (as WobblyPossum posted) then it might be closer to the Recce LW in weight but I don't know.

As an owner of one of the first Omegas I would urge you to consider a dedicated 5.56 can with lower back pressure.

Cans have come a long way in the 10 years since the Omega came out and most “Do it all cans” are comprises. OK doable for occasionally use but for dedicated to use you want a dedicated can.

[Robinson]

As an owner of one of the first Omegas I would urge you to consider a dedicated 5.56 can with lower back pressure.

Cans have come a long way in the 10 years since the Omega came out and most “Do it all cans” are comprises. OK doable for occasionally use but for dedicated to use you want a dedicated can.

Thanks for the tip, that is good to know. I was hoping to use the can I already have since they ain't cheap and I'll have to wait on the paperwork to be processed on a new one. Plus I thought the 130.1 dB rating meant it would work well on a 5.56 AR. Sounds like there is more to consider than just the dB rating.

Okay in that case maybe I should be thinking K or Mini like JSGlock34 mentioned if I do go with a 16" gun.

[HCM]

Thanks for the tip, that is good to know. I was hoping to use the can I already have since they ain't cheap and I'll have to wait on the paperwork to be processed on a new one. Plus I thought the 130.1 dB rating meant it would work well on a 5.56 AR. Sounds like there is more to consider than just the dB rating.

Okay in that case maybe I should be thinking K or Mini like JSGlock34 mentioned if I do go with a 16" gun.

Specifically I found the weight and back pressure of the omega negatives on 5.56 guns.

There are newer, dedicated low back pressure cans like the huxworx and new Surefire RC3 and YHM Turbo 3. However, IME others like the SF SOCOM cans and the YHM Turbo k still have less back pressure than the omega.

Personally, I’ve had good luck with the YHM Turbo K, good enough that I bought the second one. The are “HUB”mount capable like the Omega.

Speaking of mounts IME the Sico ASR mount is problematic. I’ve had significant issues with them getting stuck.

Surefire's mounts are decent but they only fit SF and certain B&T cans and they have tight control over their IP. If you want a hub mount that will fix your fire muscle devices, you have to buy a Surefire training can and have D.Wilson cut it up and weld it to a HUB mount. It winds up costing $700 or more.

I’ve had good luck with the Dead Air Key-mo, particularly with the FCD stoner mounts. The Q Plan B is the best suppressor mount IME but the worst without a can.

[JRB]

Do you have a specific suppressor in mind?

Personally, I'd find a 14.5in middy BCM upper you like, preferably with the MK2 receiver, and take the pin & weld option for a Surefire muzzle brake. Then order a Surefire 5.56 suppressor of your choice to match and live happily ever after.
I'd personally go with the RC2 but you might prefer the Mini depending on your OAL preferences and how much you prioritize 'handiness' vs max suppression.

Flow-through cans are great for non-AR rifles that are tricky or impossible to tune to match the suppressor. With an AR I wouldn't bother because we've got BRT EZtune tubes, buffer weights, all kinds of stuff to use to tune it.

BCM off the shelf assembled lower. Maybe go to a VLTOR A5 but otherwise leave it alone. Use different buffer weights to match the ammo you're running and for with/without the suppressor installed.

Then an aimpoint, a decent light, and a sling and you're good to go.

[WobblyPossum]

I'm not entirely dead set against 14.5" guns. I would need to buy the complete upper separately and send it away to have my suppressor mount permanently installed. Buying a 16" gun avoids that extra step since a local gunsmith can do a normal install.

The next reason is I already have damaged hearing and a 16" gun will be a little quieter than a 14.5" gun -- I'm not sure how much.

My suppressor is a SilencerCo Omega 300. SilencerCo rates it at 130.1 dB for 5.56, but I don't know what barrel length they used to determine that.

As for weight, I am comparing a BCM Recce 16 LW at 5.8 lbs vs a Colt M4 EPR 16 at 6.5 lbs. If the Colt 6960 Trooper uses a lighter weight barrel (as WobblyPossum posted) then it might be closer to the Recce LW in weight but I don't know.

Just an FYI, the Trooper isn’t the same gun as the 6960. There’s a Colt M4 Trooper (formerly called the 6920 Trooper) which is a regular 6920 with a shaved front sight base and the same Centurion MLock rail the 6960 has. It looks a lot like the 6960 on the outside but the Trooper has a government profile barrel with a carbine length gas system. The CR6960 has a lighter weight profile barrel and mid-length gas system.