300 blackout help

[benchmstr]

I'm very new to this round but am really wanting to build a suppressed SBR upper for work/fun gun..

What sbr length have y'all found to be the "sweet spot" for this caliber?

My goals are as follows...I'm wanting the suppressor to fit under the handguard, for it to be quiet, and short...that is all!

Any help y'all can give me will be appreciated

Bench

 

[The Lawn Ranger]

I shoot a 10.2" Noveske ss barrel and love it.

I do not have an adjustable gas block so some factory ammo (mostly supersonic)

fails to lock the action open on the last round. I will reload this round eventually

to remedy that. The 300 b/o as a suppressed SBR is the cat's ass. Too much fun.

 

[Retooferab]

I have a 10.5" on mine. It's very accurate with sub sonics. I don't shoot super sonics through it. I just don't see the point.

 

[dawson08]

Daniel Defense or Spikes Tactcial. 9" and both of there handguards will let you thread the suppressor inside them (depending on what suppressor you use). For the quietest rounds use the subsonic's loaded with the 208grain AMAXs.

 

[coryj]

I had an upper I built around a Wilson Combat barrel. I believe it was 11.3" (unsure now as I sold it). It was fun for a while, but I ended up selling it and I don't see myself going back to a blackout in the future. It functioned with sub/supers both suppressed and unsuppressed which seems rare for some other barrel/upper manufacturers. It was rifled 1:8" and shot subs and supers equally well.

 

[EricCartmann]

8.5" for guns shooting subsonic with Silencer

300 BLK subsonic is a slow moving round, not much chamber pressure, or muzzle blast. The Barrel for .300BLK should last a lifetime, and you will get no silencer wear from muzzle blast. If you only plan to shoot subsonic with Silencer I would do 8.5".

 

[eracer]

Mine is a Noveske 8" model, and it works fine with a can hanging off it. 100% reliable with both subs and supers - no switchblock needed. I put it on a friend's M-16 lower, and with the subs it was a brass fountain. So much fun (I wish I could afford a registered lower...)

I do note that Noveske no longer shows the 8" barrel version on their website. Maybe 10.5" is what they consider a 'better' barrel length for the cartridge.

 

[eodcam]

I heard that the round was designed around a 9" barrel

 

[Hammertime]

I went with the AAC upper in 9 inch and love it, other than the hand guard that it came with. At the moment I use my Cyclone but should have my stamp for a SDN-6 any day. I like the look of the hand guard over the can, but want to be able to remove the can once in awhile. Shoots 220 Subs with or without the can with no problems. The little SBR is shit hot.

 

[jwb47]

8.5 inch cmmg is what Im packing . will shoot subs and super sonic suppresed or not . suppressor is a yhm phantom

 

[EricCartmann]

I noticed that Noveske uses Pistol Length Gas System for all their barrels, even their 16" ones. They also use 1/7 twist for all their 300BLK barrels. Thinking Noveske barrels/guns are designed more for reliable cycling of subsonic ammo, but I am sure regular ammo also works just fine.

 

[Smokerroller]

I am planning a 300BLK build that will be an 8.3" Noveske with 30P1 or BA. Seems most fokes can get any length to run and there are lemons in every size. My requirements are ACCURATE, QUIET, & SHORT. I will also be running supers through is for my general carbine. We will see what it will produce for an effective range. I am optimistic it will be very useful and practical with Both subs and supers.

 

[Cornholeo]

I'm using the Noveske 8.2BLK LoPro upper with a SAS Arbiter can. Setup according to Noveske's rifle build using the heavy buffer, 220SMK subs are flawless and lock back bolt everytime. I am working on 175SMK sub loads because I have them handy and they are cheap to get pulls. With the 175s I went to a standard buffer and am getting good lock back on bolt everytime. Accurate little mofo for what it is built for. Wnet with a Meopta 1x4 for optics and it is a nice lite little package. Good luck, you will love it as a SBR!

 

[gixxerk8]

My 10.5 Noveske runs flawless with subs and a 30p-1. Recently switched the spring and h2 buffer to a JP silent captured spring and it slill runs like a swiss watch without the schwaaaang spring noise. Also accurate for what it is and fun to shoot. Something about hearing the slow 220 hitting the target being loader than the rifle cracks me up.

 

[EricCartmann]

Made a list of why I think 300BLK is the answer we all have been looking for.

1) It's nice to get 30-30 power from your 556 gun with only a barrel swap. Talking about 1900 fps out of a 9" barrel for .308 147gr FMJ bullet. 5.56 bolt (bolt face) and 5.56 mags are abundantly available, so no need to add cost for building up or add spares.

2) Uses .308 bullets, a very common bullet that you can even get pulled down for, such as 147gr FMJ, sometimes as low as 10 cents a bullet (before the craziness hit). Also the variety of .308 bullets is pretty awesome. Anything from 110gr to 220gr.

3) Same gun (with a pistol length gas system) can shoot both subsonic and supersonic ammo and reliably cycle without any modification to the gun. 220 gr Subsonics at about 1000 FPS will have more energy than a .45.

4) Cases are available in surplus - just need to modify your 556 cases, it's easy and fast. They have cutting kits available now in case you do not want to make your own. To reform the brass, well can't go wrong with Lee, they work and are inexpensive. Total price for a custom made case conversion kit will only be about $100.

 

[Phezzik]

I've recently built two .300 BLK uppers, the most recent being a 8.3" noveske/RR hybrid. RR receiver with 8.3" noveske and 12" YHM modular free float. Runs exclusively with a AAC 762SDN6. Interesting project because I had to mill out the forend in order to be able to remove the can. Uber reliable so far with no failures to report, running supersonic and subsonic .300 BLK as well as .300 Whisper. I'll post pics when I get back to the shop.

 

[bluto77]

I have an AAC with 9" barrel on the way and SDN-6. Can't wait! Just need to find some ammo. I'm planning on mostly shooting supers through it as I'm going to use it as a Hog.Killin.Machine.

 

[Mortar Maggot]

I have the Noveske 8.2" with the 7" NSR rail, an AAC Brakeout, and an SDN-6. Mine is a pistol not SBR, due to a stupid law here, but in five years freedom will be mine.

If you plan on adding a DBAL there is not a whole lot of room on the rail system, so choose your optic wisely.

Using subs and a suppressor almost all of the time I think the shorter the better.