My turn at a SBR

[Erick]

I am looking to going the SBR route sometime this year.

I think the main purpose is to have a nice run and gun rifle that I can suppress. I have a Smith M&P Tac 15 that would be perfect but I am a little apprehensive to cutting the barrel down on it. Any reason not to? What will I lose by hacking of 6"? The downside is that it's my only AR.

My second option is building one from a 10.5" AR pistol then adding a stock after the approval. Will the pistol markings interfere with this idea?

The third is building one from either the 300BLK or a 9mm. I have 9mm ammo, but like the idea of having the 300BLK for hogs.

The suppressors will either be the 762n-6 or 45 Tirant depending on the caliber.

Any help deciding would be appreciated!

 

[CAR-AR-M16]

Option 1: Instead of cutting the barrel, just replace it with a new short barrel. Not worth the cutting and gas port work in my opinion.

Option 2: Markings on the pistol lower have no meaning when you SBR the lower. You will have your info engraved as the maker of the SBR.

 

[Ignored Member]

Do not cut the barrel. You'll run into reliability problems with the gas system.
If you go 9mm you can make it as short as you want because it's a blowback and doesn't rely on gas tubes.
For hogs I would go with the 300blk or just stick with 5.56/.223

 

[Sharingan]

I went the .300 aac blkout route.. I love that damn round.

 

[Glocktogo]

I am against any 5.56 barrel below 10.5" unless it's just for play. The flash and blast are horrible, most 5.56 suppressors are not warrantied for under 10.5" use, ballistics are terrible and there are so many better choices. Just order a 10.5" upper from a quality manufacturer like Daniel Defense, Bravo Co., etc.

If you want a really short barrel, get an 8-9" in .300 Blk or a 5.5-6.5" 9mm. The Blk is a better choice because you don't need a 9mm hammer, buffer, mag block, etc. If I were doing a 9mmm upper, I'd do a dedicated 9mm gun.

As recommended, don't cut your current barrel. Get one designed for the intended length to avoid even more potential problems.

 

[Ignored Member]

You don't need a 9mm hammer if you use a ramped bolt, and you can run a carbine buffer as well.

 

[338Shooter]

Drilling the gas hole to the proper diameter is not a big deal when you shorten the barrel and rethread.

 

[MrShooter]

You don't need a 9mm hammer if you use a ramped bolt, and you can run a carbine buffer as well.

Make sure you use the M16 type hammer. The ones with the flat face not the notched if you are using a ramped carrier. Regarding 9mm ofcourse. CMMG makes the ramped carrier and hammer.

The notched ones cause light primer strikes

 

[jakerz]

I went with a 10.5" LWRC SBR (piston) and couldn't be happier. I opted to buy the complete SBR to not deal with my own markings on the lower receiver. I personally like to keep DI setups no shorter than 12.5". But that is just my personal preference. I would love to do a 9" 300 blk one day as well.

 

[Erick]

Is it possible to do a multi-caliber SBR? I would like to start off with a 10.5" .223 and also get a short .300BLK and a .22LR conversion and a 9mm conversion? If I get the multi-cal lower, will they allow me to change the uppers whenever I want?

Is it too much to ask that I want all my uppers to be short and quiet?