Looking for thoughts and opinions on barrel length and idea optic for a 300 blackout pistol.
I have considered a 300 blackout pistol for a while. Does anyone have any negative or positive thoughts on 8" barrel with 1" break on it? Would probably throw on a 9" rail.
I am also thinking of an aimpoint for it! I did get offered one heck of a deal on a meopta 1-4 K-dot… is magnification a total waste of time on something like this?
Just looking for some quick thoughts and opinions…
Lots of folks go with 8"-9" in 300 BLK. No reason not to go that short in 300 BLK in an SBR or pistol IMO.
Note if you run a flash hider or side ported comp, a 9" rail will probably be too long.
I mocked up a 9" KMR on a Noveske 8.2", and it wasn’t going to clear. You probably need a 7".
Lots of folks run the Aimpoint T1, T2, H1 and they are all nice choices.
-john
Really the decision depends on use. I don’t mess with AR pistols, but many SBR’s. I would be hesitant on running a brake, unless something like a MAMS pictured earlier as blast can be worse. A shorter rail than 9" would be needed for that barrel length, you don’t want the rail to extend beyond the crown of the barrel. It is just easy to buy an AAC 9" upper for most. It’s hard to go wrong with Aimpoint optics they are great, but they may not best, just depends on the application.
Howdy,
Based on a lot of research I went with a 10 1/2" barrel for my .300BLK with a pistol gas system for reliable function.
Plus it makes it easier to reach 1,050-1,070 Ft/sec with the 220-260gr bullets for subsonic loads while keeping the pressure and muzzle blast down. Also adds about 60 or so ft/sec on supersonic loads when compared to an 8" barrel.
Just my $.02 and your mileage MAY vary.
Paul
From what I’ve read, a 9" barrel is the point where you get the maximum velocity. Longer and you’re just adding weight (but also adding sight radius), shorter and you’re losing power.
Howdy,
Based on muzzle blast, the flame coming out the end of my 10 1/2" barrel using H110 powder,
I have to disagree.
Not necessarily comparing apples to apples but for example:
I have a Kel-Tec PF-9 with less than a 3" barrel, a Lone Wolf 4.6" 40-9 mm conversion barrel for My Glock 23, a semi-auto Sten pistol w/ an 8" barrel, and a Marlin Camp 9 with a 9" barrel. I have fired numerous loads through all 4 barrel lengths including a 10 1/2" barreled AR-15 9mm and even with a fast powder like Green Dot the longer the barrel the faster the bullet. Actually was only a slight difference in velocity between the 10 1/2" barrel and 16 1/2" barrel. Peak velocity was probably at 13" or so with GD.
With a slower powder like Blue Dot there was a noticeable difference between the 10 1/2" barrel and the 16 1/2" barrel. Even comparing the 8" barrel to the 10 1/2" barrel showed and increase of an average of 60 ft/sec with 147gr JHP bullets.
My testing with my guns, my reloads, my chrony and range so your mileage MAY vary.
Paul
You still get more velocity with a greater than 9" barrel, but the difference isn’t as dramatic as with .223/5.56.
With supersonic loads, the curve in the comparison between velocity and barrel length happens at a reduced barrel length for 300 Blackout compared to 5.56. The velocity gain still exists in the longer barrels though. In practicality though, it would be hard to justify the gain going beyond 16" for the blackout, as would 24"-26" for 5.56. Depending on who you talk to, 8.5"-10.5" seems to be a good balance for 300 Blackout, with 14"ish-16"ish for 5.56. you can make them shorter or longer for either. The ideal choice really depends on the users needs.
Howdy,
Since the 300BLK uses pistol powder or a very fast rifle powder I agree that using a barrel long that 16" would really be a waste of…barrel steel.
I’ve seen too many people on other forums complaining about slow velocity and everyone of them had 8 of 9 inch barrels.
Same thing with function.
I read and study long and hard before I decided on a 10 1/2" barrel.
5.56mm with a short barrel? I’ve used a regular 20" barreled M-16 “in the field” several times and decided to add a 10 3/4" barreled CAR-16 Commando for a PDW when I used a bolt-action rifle. First time I used it in the field with the same old M192 55gr load I was like “WTF?!?!”
Paul
Given the same gas system a longer barrel will mean a longer dwell time which may improve functioning with subsonics, especially if you’re using bullets < 200 grains. That’s one reason I went with a 12.5" AAC upper, I’m using the Lehigh 190-gr. maximum expansion bullets and still get perfect functioning at 1000 fps. This may or may not matter to you. The velocity increase is small and the longer sight radius won’t really matter if you’re going to be using a RD all the time.
I put an Aimpoint H-1 on mine and I love it but I’m considering changing to a 1-4X variable just so I can have different measured holdovers and/or mark the turrets differently for subsonic and supersonic loads. (Not to mention that the older I get the more difference a decent 4X scope makes even at 100 yards.)
I wanted to go with the AAC 9" bbl but can not find one in stock. I am am going to buy a Noveske 8.5" bbl with their low pro gas block and gas tube. https://dsgarms.com/nvb-8-300blk
This is tempting too but I don’t know anything about their gear. https://dsgarms.com/dsgu-300-10-mcsr10-agb-a2
http://www.ar15.com/forums/t_7_22/1448200_WTS__New_AAC_Advanced_Armament_9_300_blackout_barrel.html
Not a bad deal. I got the same setup a while back for $275 on TOS and sold the FH.
I got in a pissing match with a MOD over there and banned from their E&E. Too bad because that’s what I enjoyed the most over on TOS!