Wednesday, March 5, 2014

Anybody Running .300 Blackout?

Actually, I was going to title this, "Anybody playing with 300 Blackout", but we're serious gunnies, right?  This isn't play, this is training.  I'm playing. 

But to the point, ARs are like potato chips: you can't stop at one.  Y'all know I have my home made AR, in 5.56 - everybody's favorite poodle-shooter cartridge, right?  The biggest advantage of .300 Blackout, from what I've read, is that it's 30 caliber and the whole idea was a compromise intended to get 30 caliber into the M-4/M-16 platform with minimal changes.  Well, I have a DPMS .308 AR-10 clone, a .308 Scout rifle, plus a pair of M1 Garands and a Remington 700 BDL in .30-06.  Not to mention Mrs. Graybeard's .30-30 Marlin.  I think we have that 30 caliber niche pretty much filled in. 

So, while I've been noticing the .300 Blackout thing going on around me, I haven't entered the game.  I suspect it's not worth it for me, and I should go for something else in the AR platform for my next project.  What's it going to be used for?  Punching cardboard for fun.  I have a 200 yard range anytime.  Longer is possible, but 600 is moderately inconvenient and 1000 yards much more so. 

I'm thinking it's either .458 Socom, or one of the slightly bigger calibers like 6.8 SPC or something.  
(Left to right: 223/5.56 NATO, 6.5 Grendel, 6.8 SPC, .458 SOCOM, and .50 Beowulf) (source page)

Opinions appreciated.  Other than "your gun sucks and you're holding it wrong". 


  1. just got done watching Michael Bane on Shooting Gallery shooting the 300 Blackout. I wasn't too impressed and he didn't seen to be either.

  2. I do .300 Blackout here. But I adopted it because I want to build a short-barreled suppressed rifle and the cartridge is perfect for that.
    I do have a "standard" AR that I built previously in .300 and I like it. Think 7.62x39 from an AR using AR mags.

  3. Murphy - right. Everyone knows 7.62x39 is lower power 30 cal round than a .308 (7.62x51), and subsonic was part of the design concept. Which really helps in suppressors.

  4. 300blk is a niche does some things well. If you need those things then it is a viable round if not there are other options that may be better. One BIG advantage is that you can build one easily in that the ONLY dedicated part is the barrel. Everything else can be standard AR parts. Also if you reload you can cut used 5.56 cases down and make 300blk cases.

  5. Lemme paraphrase (I think) what Murphy was getting at...

    Supersonic loads of .300 BLK are literally identical to 7.62x39 in performance AND can be used in AR magazines whereas actual 7.62x39 really can't because of the case taper.

    In many ways it's a non-trademarked .300 Whisper which has been done before as a wildcat (.300 Fireball and .300-221 Fireball). For decades it carved out a loyal niche and never really took off. There's probably some valid reasons why not and they're probably related to the performance.

    That's just spit-balling though.

  6. 300 BLK is great for close quarter suppressed which it, like J.D. Jones' 300 Whisper which Angus mentioned, does quite well.

    Also as Angus pointed out, if you need a 7.62X39 that feeds through AR mags, 300 BLK is it.

    Which is also a downside to it; since 300 BLK fits and feeds through AR mags it's possible to have one sneak unnoticed into a mag full of 5.56, and there have been reports of rapid AR disassembly from that. It seems some 5.56 barrels are just deep-throated enough to allow chambering a 300 BLK deeply enough to establish battery. Unfortunately, a 5.56 barrel and a .308 bullet produces an interference fit.

    If it's just for play, consider the 6.5 Grendel. Indications are that it's superbly accurate, and 6.5 projectiles carry energy very well. And, while factory Grendel ammunition is no harder to find than glass-cased ammo for the 2.95 Skiddenboomer Ultra, but not a big deal to make yourself. If it's for play and practical use, the 6.8 is the better choice, but it's still a boutique caliber, and will be until we start seeing 6.8 on the shelves at Chinamart.

    Or, stick with what works and buy several more cases of 7.62X51 and another AR-10.

  7. If you're not going to put a can on it or use it for hunting, there's not a ton of point to .300 Whi... I mean, .300BLK. (Then again, much the same can be said for most of the other alternate caliber choices.)

    Just for playing and having something different, I'd still be a little tempted by the BLK if only for the fairly ready availability of ammo.

    (The 6.5 Grendel is the choice for long range paper shooting, but 6.5 Grendel on a 200 yard range is like driving a Lambo Gallardo up and down your driveway.)

  8. Ditto on 300 AAC Blackout having fairly good ammo availability.

    Of course, if you're willing to buy an off-the-shelf solution instead of rolling your own, there's always Alexander Arms' .17 HMR as an alternate-caliber AR solution. .17 HMR ammo is both available and reasonably inexpensive, while still performing acceptably out to 200 yards.

  9. I have a .300 Blackout pistol upper. I drilled out the gas port slightly for full reliability with suppressed subsonics. Runs great now. I love it, but I bought it strictly for suppressed subs, so that may not be what you're looking for. I sold my .450 Bushmaster upper recently, in the hopes of financing a .458 Socom (which I'd also like to eventually run suppressed).

  10. At one time or another I've had 6.8, 458 Socom, and 50 Beowulf. The 50 & 458 are AR 15 sized 45-70s. Fun but they do kick a little. Brass and ammo are very expensive and hard to find. 6.8 SPC is a great round, but no cheap brass or blaster ammo available. A friend has a 6.5 that he uses to shoot cow elk. Works good but 2500 fps muzzle velocity limits its energy. My 300 Blk is a blast. I shoot 245gr lead bullets out of my suppressed SBR. Great fun. I gave up on light bullet blackous because of 12 to 18 inch zero difference at 100 yds from subsonics. Enjoy

  11. I've got an AR in 300 BLK and when suppressed it is the cat's meow, when unsuppressed it's still fun too.

    That you can also imitate 7.62x39 ballistics is a plus, not to mention the variety and availability of .30 cal bullets for reloading.

    Easy to shoot with barely if any more recoil than a standard 5.56, it gives you a nice suppressed platform and a decent hunting capability if you like that kind of thing.

    With the right suppressor and subsonic ammo, its as quiet as a suppressed 9mm, but you're getting rifle caliber performance out of it.

    Also and importantly, its fun to shoot suppressed or unsuppressed.

  12. Even the 6.5 Grendel isn't that much better at long range shooting than regular 5.56x45 loads with long heavy match bullets.

    Yes my buddy shoots his 5.56 to 1,100 yards with single load bullets. 800 yards is no problem with mag length match bullets.

    What you get with the Grendel is a little better wind bucking ability, and you meet the caliber minimum for hunting in some states where 22 centerfire doesn't.

    The 300 BLK is not a long range number. But if you need a short range subsonic sniping round, it's a decent choice, or need to hunt deer at close range with something bigger than 22 for legal reasons, that is also a good reason to have one.

    So if you design a rifle around a purpose, then the 300 BLK can be the right round to build on. But for general rifle use, I'd build another 5.56 any day.

  13. My feeling going into the question was that .300 BLK is a niche round, and virtually all the comments reinforce that idea. It has its place, for sure. I don't think I'm in that place.

    Thanks for all the great comments! Some great lines in there.

  14. Shot them, they function well and provide AK performance from an AR. For CQ shooting suppressed or not they are a cut above the 5.56. Anything over a couple hundred yards, not so much.

    For longer ranges, I like the 6.5 caliber. Excellent SD, VG ballistic coefficients, widely available projectiles. In an AR platform, I'd look really hard at a 6.5 Grendel or equivalent. The 6.5 TCU in AR is also interesting.

  15. If you just want a different upper to have a different upper, maybe just build a different 5.56?

    If the one you have now is a 20", build a carbine, or a 24" free-floated heavy-barrel target gun or something.

  16. I love my 300black rifle. I am going to get an AAC Handy rifle in 300black. Its a great round, I have hunted pigs with it both supper and sub sonic ammo. It just works for sub 200yard shots. The single biggest selling point of the 300black is that the only special thing you will need is a different barrel and muzzle device, everything else will work with a normal 223/5.56 rifle.

    That was a big selling point for me, that all of my magazines would work, with my new rifle. And that is why my next build will be in 458 Socom because i will not need to buy all new magazine for it to work.

  17. I liked my .300 Whis... er ".300 Fireball" AR. I like my custom Mauser in the caliber. I generally like the chambering.

    Silicon Graybeard didn't ask me if I liked .300BLK, though.


    And you're holding it wrong. :p

  18. Tam, you said, If you just want a different upper to have a different upper, maybe just build a different 5.56? (rest snipped)

    What's really motivating this is that I have a couple of "0% lowers" - forgings or castings with no machining done. I got those as a project to increase my machining skills, and got thinking about what to do with a finished AR lower once I have one. More of "what do you make of this?" than looking for another upper.

  19. Practical Tam would of course suggest building a near-duplicate of your existing rifle. ;)

    Fun Tam would say ".450 SOCOM is shiny!" :D

  20. Tam.
    That mouser in 300blck, is it a older one converted over, and if so who did it? (i got an old k98 that wont shoot worth shit) Or is it a new rifle you had built up?

  21. Tam - should you come back by to see if there were any followups -

    Practical Tam would of course suggest building a near-duplicate of your existing rifle. ;)

    Fun Tam would say ".450 SOCOM is shiny!" :D

    See, practical me is saying the SOCOM round looks pretty cool and it runs with an AR lower.

    Fun SiG is saying, "screw the AR lowers, let's build a 50 BMG!"

  22. Bradley,

    It's a rather elaborate conversion on an old Turkish tomato stake.


    Now a BMG is definitely fun. :D

  23. Is .300 Blackout what you shoot at transformers?