Dedicated Suppressed AR vs. Standard AR Suppressed Results

I picked up two suppressors today, my M4-2000 and my Pilot 2. I was not expecting a Pilot 2 at all, M3 told me he was selling me an original pilot. Not sure what that shows on his part but I am beyond elated to get the upgraded model that allows disassembly.

I was really looking forward to shooting my dedicated suppressed SBR. I have written about it on here countless times, its a build that has taken since August to complete.

It has a Noveske upper receiver with a DD barrel cut to 10.3". The gas port is 0.058" (I measured it) When I first fired this, it would not cycle unsuppressed regardless of ammo or buffer weight. It just barely ejected the spent case but would not pick up a new one. The rail is a Centurion 9" and currently has an H Buffer with USGI spring.

I checked all three rifles first for concentricity, I just eyeballed it. I trust BCM/ADCO enough that I wasn’t very concered with any baffle strikes, but I wanted to at least make sure there wasn’t something that was glaringly wrong. I started off with the dedicated suppressed upper.

I had M193, PMC Bronze .223, and PMC XTAC M855 with me. All cycled flawlessly suppressed. M193 would cycle unsuppressed, but barely. Not sure if the rifle is “breaking in” or something, but that was a surprise.

Recoil was non existent. It was very very smooth, there was no gas blowback, and the upper was pretty clean considering the suppressed firing.

When I picked up the 12.5", I thought that it was perfect. Its barrel was just long enough to justify the ACOG’s magnification but even with the suppressor on it it was not unwieldy or front heavy. I was surprised. It felt very very balanced. This is probably my new favorite rifle.

However, it is definitely not comfortable to fire suppressed. With the short eye relief, the increased felt recoil and the “gas face” it was not as fun as the 10.3" (It should be noted that I was not using eye-pro specifically to see if gas would get in my eyes [stupid, I know]. WIth a good set of eye pro there would probably be no issues)

No surprise here, this was the most awkward to fire with the suppressor with 14.5" of barrel. It was still not uncomfortable but hanging 16oz off the muzzle of an already longer weapon made it a bit front heavy.

This too suffered from the same problems the 12.5" AR did. I would not like to fire these weapons suppressed for very long.

I will need to put a Vltor A5 buffer assembly on the 14.5" lower and the 12.5" lower if I plan on shooting suppressed at all. Every shot feels like the buffer is bottoming out on the buffer tube and causing it to beat itself to death. I’m sure it didn’t help that I was only using an H buffer.

I’m extremely satisfied with building an upper from the ground up to be shot suppressed. It is a completely different rifle than the other two with the suppressor attached. I’d bet that it feels smoother than most unsuppressed ARs.

I am really going to run it through its paces on Thursday; I’ll be firing about 500 rounds through it and I can’t wait to see if it can maintain this standard of reliability. Of course, that is more important than felt recoil or gas blowback.

Congrats!

You’ve got a nice stable of runners built up there.

Does the 10.5" have any other “special” BCG parts like Grant’s, or is the only unique feature for suppressed operation the extra small .058" gas port?

Did the DD barrel start out as a 16" CAR gas?

No. I wanted to have Grant tweak it a bit (play around with springs, bolt carriers, buffers, etc) but didn’t want to send it in until I had my suppressor because I wanted to shoot it in its original configuration suppressed before I did anything else to it. (That way if for whatever reason it did not work suppressed, I could start eliminating things). Now with Christmas around the corner I will wait until after the new year to do anything, but I do have plans on tinkering with it for optimal function.

Yes.

I thought that the correct port size for a 14.5" or 16" barrel on a carbine gas system was .061" and .063" respectively, how is it that the cut down DD barrel has a .058" gas port? Or am I not understanding something?

Thats the size of the port that is on my rifle. Surf, another member here, has also measured DD carbine gas barrels with similar port sizes.

But you are correct. 0.062" seems to be the standard port size on Colts.

Euro,

I also have a 12.5" and if you run it with an H3 or A5 you will like it. Did you not open the port up on the 10.3"? I think it’s a mistake not to in my opinion.

I will eventually. I understand your reasoning and it makes sense. I just wanted to run it suppressed before meddling with anything.

Should I buy an H3 or get an A5? I know your answer here will be to get an A5 but an H3 is significantly less expensive and takes 30 seconds to install. Still get the A5? I know I need something, that recoil impulse is so intense it feels like when the damn BCG bottoms out on the buffer tube that it stays stuck back there for 1/4 of a second before returning to battery!

The A5 may not be for everyone. So just consider getting an H3 and a blue Springco spring. That will make a difference (at least in my experience).

I wonder if the LMT Enhanced Carrier (not bolt) would do anything to bleed off the gas?

Also, IG, what do you mean when you say that the A5 isn’t for everyone?

Some people don’t want to spend the money. In that case you use alternate methods. Personally I think the idea is good and so far most of those who I know that use it, like it.

One has to understand and appreciate the versatility.

I think for a dedicated suppressed gun, opening up the port would ruin it’s purpose.

IMHO, for a dedicated suppressor host .056’‘/8’’ is perfect, for a SEMI-dedicated host .062’’ would be better.

I need to break my other rifles in a little more so the ports erode a bit. Or I might just have 'em opened up a little.

I’ll echo Gunz. The A5 requires a little more money to buy the RE and Buffer/spring. But a simple heavier buffer can help most guys in the short run.

On a defense gun you want to run well over the long haul… a rifle buffer or A5 is the way to go.

Well I will not be shooting the other two ARs suppressed very often, so I think I will go the H3 route. For the price of 2 A5 assemblies I can get another flashlight.

I am not ruling anything out yet though.

Put it this way:

Given a 14.5" barrel with a certain port size, the same port with a 16" barrel will deliver more gas.

To keep the total gas delivery the same, the 16" should have a smaller port.

If a .0625" port is optimum for a 14.5" barrel, something smaller like .060" will be optimum for a 16".

Great post Euro!

I’ve been interested in doing a similar project for quite some time now. I really like the idea…but I’m still a little concerned I would run into issues unless I was running full-powered Ammo and the suppressor all the time. My plan was to only cut to 11.5", use the A5, and the enhanced carrier though. It was my line of thinking that this would allow me more leeway for running unsuppressed, and .223 powered loads.

I’d be very curious to see how an A5 buffer system and LMT enhanced carrier would factor into your dedicated upper’s performance.

Yes, it will bleed off some I think.

C4

I’m thinking of a similar build as his (12.5" suppressed with standard GP size) and was wondering if the LMT Enhanced carrier + Vltor A5 would make it a much smoother shooting gun without sacrificing reliability?

It certainly wouldn’t hurt, but would NOT be the same as using a Noveske SB or a dedicated (suppressed) barrel.

C4

Gotcha. Didn’t think it would, but I wouldn’t want to go dedicated on the 12.5" anyway. I’ve decided on the Ops Suppressors, and I hear they don’t cause as much backpressure as end mount suppressors…don’t know if that’s true or not?

As an alternative to a dedicated upper, what about a dedicated suppressed BCG to go along with the suppressor?

The special BCG would offset the increase in gas drive caused by the suppressor.

The combination of the special BGC and suppressor would be able to drop into most standard uppers and retain the same cyclic rate.