7.62x51 sbr vs 300blk sbr

[Bolt_Overide]

All other things being equal, ammo costs not taken into consideration, what is better overall? I'm concerned with effective range, accuracy, and effect on target. I'm looking at a 8.5 300blk and a 12.5 7.62, same suppressor for either, griffin recce 7. Will also be using the same optics on either, so the round is the only variable.


Thoughts?

[H Wyman]

Is this a do-over from August 2013?

https://www.m4carbine.net/archive/index.php/t-136570.html

[IraqVet1982]

Weight - win goes to 300blk
Full velocity rds - win to 308
Subsonic - draw, its a 308 bullet going at 1100fps or less. You might have issues with cycling 308.

[Bolt_Overide]

Is this a do-over from August 2013?

https://www.m4carbine.net/archive/index.php/t-136570.html

lol I must be getting too old, I have no memory of posting that.

[JCast265]

I would think you'd have a lot of wasted powder in a SBR .308 whereas the .300 is optimized for it. Not to mention the longer receiver length, weight in a small package, and potential for cycling problems in the .308

[chakup]

My $0.02- SBR full frame AR would be fun but limited. However SBR "Ar15" leaves you lots other options as well for fun uppers.

[jack crab]

Make sure the rifling twist is fast enough for subsonics if intending to use them. 300 Blackouts seem to have a 1:8" or faster twist. Most .308s are running 1:10" or so. So, the typical .308 running heavy subsonics may not sufficiently stabilize.

[Leuthas]

lol I must be getting too old, I have no memory of posting that.

I try not to post much in needlessly rehashed threads but... this is goddamn funny.

[Stengun]

Howdy,

Gee, I have numerous firearms, both longguns and handguns and each one has a dedicated and/or practical purpose and I have a really hard time of coming up with a purpose for a .308 AR SBR from a civilian standpoint.

I would also be concerned with the effect that full power loads that were developed for a 24" barreled rifle would have on a suppressor when fired from a 12.5" barrel. Without a suppressor the muzzle blast would be hard to tolerate even with hearing protection. I've used a 10 3/4" barreled CAR-16 Commando in CQB and now I cannot hear thunder.

Paul

P.S. I do own a 10 1/2" barreled .300BLK AR.

[RWBlue]

I would think you'd have a lot of wasted powder in a SBR .308 whereas the .300 is optimized for it. Not to mention the longer receiver length, weight in a small package, and potential for cycling problems in the .308

IMHO, you are correct.

I have a 300-221 SBR AR (300BO, wildcat).
I moved the 308 suppressor to my AK 7.62x39
and M1A.

I had issues getting subsonic 308 and 7.62x39 to fly straight, I don't think I ever got anything to cycle the guns.

When I was testing I couldn't get subsonic rounds to expand/fragment. Assuming the bullet construction has improved with the 300BO and you can run it subsonic, I think that is the best round for what it does. If you have to go supersonic, then there is no reason not to gun up to 7.62x39. If I need to go with 308, it will not be subsonic or SBR. It will be for long range work.

[BillBond]

My vote is for the 300blk.

[daddyusmaximus]

I've considered going the SBR route on my current .308 AR build. I'm just looking to get more punch out of a 30 cal then I can get out of my 5.56. I want accuracy at short range (<300 yds) and would like the ability to fit in in a small carry case. Looking at both 12.5" and 16" Rainier Arms UltraMatch .308 Barrels. I still haven't ruled it out, but if I was concerned more about running a suppressor, I'd just go .300BO. The .300 is only a bit better than a 5.56 and IMHO not worth getting into for normal shooting, but if I was going to run silent, (and I want to one day) it's worth it.

[ad_infinitum]

I have fallen out of love with 308. Ammo is too heavy, SBRs seem like a waste in this caliber, recoil is more significant.

7.62x39 or 300BLK are short and sweet. Much less recoil, all the practical accuracy and power you need.

For an exotic solution, 6.5 Grendel or 6.8.