Duty SBR with suppressor

[sgtkeebler]

My department just authorized the use of SBR as patrol rifles, but they have to have a suppressor. Since I have been wanting a SBR for a while I'm going to use this as a great reason to get one. I have a AAC 762 SDN 6 that is in ATF jail, hopefully July/August.

They don't allow frankenguns must be purchased as a complete rifle.
Here is what is approved in my price range:
Colt - 6945 - 10.3" Barrel
Colt - 6933 - 11.5" Barrel
DD - MK18 - 10.3" Barrel
Sig Sauer - M400 - 11.5" barrel
Tac Pro - MOE15 - 11.5" Barrel

Anyone have experience with any of them and recommendations?

 

[USMC_03XX]

I am a fan of DI AR's - why? Because I have run them a LOT and they work. I am very familiar with the mk18 system, and the Colt 6945 is a solid option. I have never run a mk18 with a 762 can before, however. DD would be my 2nd choice although there is probably negligible difference between the two. I have been eying specialized armaments mk18 upper that has a dedicated can on it, the system has been designed to run suppressed and negates the over gassing - with the drawback of a dedicated can and price tag...

 

[sgtkeebler]

I'm most likely going to be getting a 5.56 can in the future so the 7.62 will be temporary. I really want the saker but they haven't approved it for duty use.

 

[Cobracutter]

Def get a 11.5.... I would go with either a BCM SBR , KAC SBR or a Colt 6933.
Ballistics, reliability, reduced wear&tear and reduced chance of baffle strikes all favor the 11.5. Without a Adjustable GB you are going to be dealing with some blowback.

Personaly, I would scrap the SBR Idea and get a 14.5 or 14.5 +Pin and stay non NFA. There is no point to go SBR if you HAVE to stick a can on. Unless you are running through methlabs then you are handicaping your ballistics and maybe rifle length going with SBR+CAN.


The SDN6 is a shitty can so def get something better. There are other good 7.62 Cans that are more versitile, not as big, and have much more solid mounting. Then there are a bunch of great 5.56 cans as well. If you are dead set on a SBR, go with a Mini can to keep it as small as possible. You are already limiting your ballistics, don't limit your manuverability/handiness more than you have to.

 

[USMC_03XX]

Cobra is right on reduced wear and tear with the 11.5" bbl. I will say I have shot 10's of 1000's of rounds through a 10.3" bbl - mostly suppressed, and have been around probably close to 1 million suppressed rounds without ever seeing or hearing about a baffle strike with the mk18.

 

[CTown137]

I use a 16" gun on for work. This is my reasoning behind it:
Not everyone that I would be with in a gun fight will have a can. Not everyone will even have a rifle. So as soon as they cork off a round I am def anyway. Plus if or when my rifle runs dry I transition to my Glock 21 which is not suppressed... again def as soon as I squeeze the trigger. I bought a quality pair of electronic ears with the money I would have spent on the tax stamp and have them right next to my rifle and I wear them anytime I pull my rifle out.

To your question.... I have fired more rounds than I can count out of a MK18 with and without a can... quality weapon that will serve you well.

 

[Hollywood 6mm]

The 10.3" barrel with the RIS II rail can have clearance issues with some of the AAC 51t mounts and cans- especially the straight muzzle brake. I run a 10.5" barrel for partly that reason.

That said, if I had to do it all over again, I probably would go with an 11.5" barrel - especially with a 10" KMR.

 

[Cobracutter]

The 10.3" barrel with the RIS II rail can have clearance issues with some of the AAC 51t mounts and cans- especially the straight muzzle brake. I run a 10.5" barrel for partly that reason.

That said, if I had to do it all over again, I probably would go with an 11.5" barrel - especially with a 10" KMR.

The KMR is also a 1.3" ID so it limits most cans to non reflex design, or running a barrel much longer than the rail.

They need to make a 1.5" ID so you can run a reflex can on a SBR, still have plenty of hand guard space, and keep the OAL down.

 

[NET65]

I have thousands of rounds down a Noveske mk18 with no malfunctions. I have seen baffle strikes on other 10.3in guns but it was always due to using frangable ammo (required for some live fire shoot house training).

 

[Cobracutter]

Not all 10.3/10.5 barrels are created equally. Nor is the type of ammo that is used. Some rounds will fail to stabilize out of a shorty and coupled with a non concentric bore, increases the chance of baffle strikes.

Hence for years most can manufactures would not warranty Sub 10.5" rifles when used ICW their Can's. I had one Can manuf tell me years ago that they would only approve of a handful of SBR barrel manufactures at the time (Colt, Noveske, LMT or one chopped/threaded by certain outfits with stellar reputation). The market has changed a bit since then but it still varies by can manuf as to what they warranty and guarantee.

There is a ton of institutional knowledge out there that has been gained through trial, error and experience. Most of the stuff we see to day is a result of something else not working, or not working well enough and this is the current evolution.

 

[Red343]

I'd run the Colt - 6933 - 11.5" Barrel just for more reliablitlity. I like the SDN-6 and think it runs good with the 5.56. I wouldn't use my personal sbr/suppressor as a duty gun in case you ever get into shooting situation.

 

[Delta4-3]

The reason for can companies not warranting sub-10.5" barrels is overpressure and baffle erosion. I personally prefer a 12.5 with a 4" can when it comes to 5.56.

I feel like everyone advising to not use a can hasn't actually "worked" with one on. The one and only time it can be a detriment is clearing very constricted structures. Even in tiny hadji houses, the sbr with a can is plenty maneuverable and will save your hearing and possibly your life. There is no reason not to run a can.

Just out of curiosity, Has anyone claiming ballistics loss from 11.5 to 10.5 done any testing there or even run the numbers? Ammo selection will have far more effect than 1" of barrel. When I run a 10.5 I end up running a longer can so it seems. I have hog hunted (and other things) with 10.5 5.56's and they do just fine.

 

[Gunfighter14e2]

I wouldn't use my personal sbr/suppressor as a duty gun in case you ever get into shooting situation.

Good advice here,.... then again the added numbers it may carry forever may be in a place that's hard to see.

 

[Cobracutter]

The difference in dwell time, reliability, and ballistics has been beaten to death with a full range of various ammo loads. It's a drastic difference between the two(with some loads being night and day with regards to velocity and frag range), and why some of the top AR companies make 11.5 and not 10.5 guns.

I think there is some confusion. The issues is he said he cannot use an SBR, unless there is a can attached. He also said it's a patrol rifle, and I assume he is not on full time SWAT/SRT/SERT/whateva doing nothing but raids and CQB.

It's a much better overall solution to run a 14.5-16" gun without a can, then be handicapped with a SBR + CAN (which will be heavier, probably have a greater OAL and without a doubt be ballistically disadvantaged).

 

[fdkay]

Do you have to use 5.56/.223?
If I were to go with an SBR, it would be in .300BLK with the supersonic loads.
It is specifically geared towards short barrels so you won't have the erosion issue.
Let's face it, with an SBR in 5.56, you are burning an awful lot of the powder outside the barrel.
I always thought that in a 10-12" barrel, the .221 fireball made more sense as the velocity would be very similar without the waste, noise and enormous fireball, as it was designed for a 10" barrel.

 

[Red_SC]

I have admittedly limited experience in this arena, but the Colt 6933 always seemed like a good setup. I put a 11.5" lightweight FN barrel on my SBR to get the same result, and I like it. I'm running an AAC M4-2000 on it, but would like to try one of the new shorty cans on it.

 

[sgtkeebler]

I wouldn't use my personal sbr/suppressor as a duty gun in case you ever get into shooting situation.

That is true, it would be shitty to lose 2 NFA items for an unknown time frame if I had to use it. I might use this as a reason to buy a SBR and just buy another autherized 16" barrel AR for duty.

 

[ZombieMonkey]

A purpose built 10.5 or 11.5 with a can for patrol is a great option, one that more and more PDs are starting to allow. I've carried an LMT 10.5" SBR both suppressed and unsuppressed for patrol. Ballistically you're not giving up much for what we encounter on the PD side of things, you will retain plenty of velocity with either length to still get the job done. Sure, not everyone may have a can, but the more you can do to protect your hearing the better.