.300 blk out question

[CANNONMAN]

I've got a friend who sent a bunch of AR 15 parts off to a custom shop. They went out of business and it took a potential law suit from a collection of similar customers to get their parts back. Now saddened he tells me he doesn't know what to do. I told him that since he has four other AR 15's why not put together a .300 blk out? This is when he tells me that others have told him they wouldn't do that and to go ahead and have me put together another AR 15 as he was going to have the shop do. I told him I had no real reason why anyone would tell him that and that I would post his issue with all the like of you who may read and reply to the question. So, why would you not want a .300 blk out? Especially if you already have four AR 15's, three are for the "having" only and are rarely shot.

 

[primalmu]

The real question is why did his buddies tell him they wouldn't? I don't see anything wrong with a .300 Blackout, but I don't have any use for one since I don't have any suppressors. You could easily say he should build a 6.8 SPC, or preferably, a 6.5 Grendel (even if only because the name is cooler).

 

[Hokie_PhD]

Some people don’t know what they’re talking about. Others repeat what they hear and the little they know.

300 Blackout seems like a very interesting option. It’s on my list, but I reload and I like the thought of recycling some damaged brass that I have into something useful.

I also like the thought primalmu has of the 6.5 Grendel.

But that’s me. Some like my brother don’t like having to too many calibers.

So each his/her own.

Personally I think you need to find out what your friend wants and needs. Then make a recommendation based on that rather than speculation.

 

[Demi-human]

I would not want a Three Hundred Blackout if I already had seven. Or if thirty caliber bullets were outlawed or disappeared for some reason. Or if I thought shooting quietly was passé. Maybe if the only range I could shoot at was over five hundred up to one thousand yards I would have second thoughts.
Perhaps if I had an irrational dislike for cases shorter than an inch and a half.

Barring the previous, I can't think of a reason not to build one in Three Hundred Blackout.

Could he have 'less than friends' who are all building Blackouts and they don't want him in the "club"?

If I listened to the naysayers I wouldn't have half the neat firearms I do.

 

[jmr40]

Unless someone wants to shoot suppressed I don't see a niche for the 300 BO. If someone has the correct barrel twist to shoot 50-75 gr bullets from a 223/5.56 barrel it does everything else better. I currently have 4 AR's, all in 223/5.56. All set up very differently, different sights, barrels, triggers, handguards, etc. for different uses and due to barrel twists even with different ammo.

I'm seriously considering adding another upper for one of them to another caliber, but it won't be 300 BO. If I go with anything else it will be one of the 6.5 or 6.8 offerings and I'm leaning toward 6.5 Grendel.

I wouldn't be interested, but having one in 450 Bushmaster makes sense too. But I have no use for 300 BO.

 

[rabid wombat]

Hmmmmmm....A 200+ grain bullet going a 1000 fps, in a compact form with a 30 round magazine (that weighs a TON compared to 30 rounds of 223). It sounds a lot like a 45 ACP in a rifle form. I went 300 BO after considering it for home defense. Penetration can be an issue.

 

[jmorris]

I guess the biggest reason is that you can chamber and fire a 300 blk in a .223 gun, with less than desirable results.

Not a problem for people that pay attention to things but is a big one if you don’t.

It really doesn’t do a lot for me that my other AR calibers can’t do better though. A 405 grain bullet at 1000fps from a .458 will have a boatload more energy. A 6.5 Grendel will run circles around it at long range. A 9mm with 147gn is a much cheaper sub plinker on powder, brass and bullets. For that matter same could be said about a 45 ACP but that would take a special lower.

I never had any interest in one until I built a machine to convert .223 brass over and had a bunch left over from “testing and tuning”. I guess it still doesn’t get used much but you can’t have one of everything without one...

 

[TIMC]

I have 9 AR’s in different configurations and calibers, 2 of my AR’s and one bolt rifle are in . 300 B/O. You’re right no reason not to build one. You can even make .300 B/O ammo out of 5.56 ammo if you want.

 

[greg_r]

I have an AAC Handi Rifle in 300 BLK as well as a a lower and two uppers, well had two uppers, I just sold one. I like the 300 BLK, and have had a long history with it and the Whisper that it was derived from. I like the cartridge, but it's not a good hunting arm subsonic, the rounds just don't reliably expand. And a 110 grain bullet at 2200 - 2300 feet per second just dosent make a good long range hunting arm. It's best used at ranges of 150 yards or less on deer sized animals. I really like shooting it though, fun range gun.

I want something with a bit more oomph for hunting though. I thought hard about the 7.62x40WT and think it would be a better supersonic performer than the 300 BLK, but in the end I ordered a barrel chambered for the 7mm Raptor. I think either of these cartridges would likely just about double the effective range of the 300 BLK, good to 250 - 300 yards maybe.

Maybe this is what the "others" were referring to when they advised against the 300 BLK????

 

[adcoch1]

300 blackout is an awesome modernization of the 30 carbine concept. It really runs best in sub 12" barrels, so SBR owners and pistol builders love it. I have both a pistol and SBR 300 blk. Very fun, but the rifle (16" carbine) I had went away, mostly because any other carbine cartridge does better with the longer barrel. But in sub 10" barrels the 300 blk is really fun for range use, close deer hunting, or suppressed use. I shoot mine with 125 grn bullets a lot, it's not JUST for subsonic...

 

[imashooter]

Idiots. They're everywhere. Build him the .300.

 

[Theohazard]

I told him that since he has four other AR 15's why not put together a .300 blk out? This is when he tells me that others have told him they wouldn't do that and to go ahead and have me put together another AR 15 as he was going to have the shop do. [...] So, why would you not want a .300 blk out? Especially if you already have four AR 15's

The terms “AR-15” and “.300 Blackout” aren’t mutually exclusive. AR-15s come in all sorts of calibers, including .300 Blackout.

.300 Blackout is an excellent caliber if you want .30-30 or 7.62x39 performance out of an AR-15 with no modifications needed other than a new barrel. [EDIT: I know it doesn’t actually match those two cartridges, but it comes close enough for most people’s purposes. It’s not that far off from the 7.62x39 with some loads, and while it’s a little farther off from a .30-30, it makes up a bit downrange due to a better BC with most bullets.] The caliber is also more efficient out of a short barrel than most other AR-15 calibers: Even out of a 9” barrel, supersonic 110 gr. hollow points will fully expand in ballistics gel at 300 yards. It also can be loaded with subsonic ammo for extra-quiet silencer use while still cycling the action.

 

[Varminterror]

There are a lot of things I would do before a 300blk.

 

[LoonWulf]

If he wants the .300, Id build him the .300.
But as the other guys pointed out there are other much more interesting options available for the platform.

.300 Blackout is an excellent caliber if you want .30-30 or 7.62x39 performance out of an AR-15 with no modifications needed other than a new barrel

This is what I had read about the .300 when i built my 16" upper, but i couldnt even come close to x39 much less 30-30 performance from it. I then went and bought a RAR, and was similarly less than thrilled.
Im not saying that people arnt getting that kind of performance, as member sent me his recipe (i checked it and it there are manuals that agree it should produce what he says), and if i ever get another blackout ill try it, but ive never managed to find a load that broke 2250 comfortably with 125s.

 

[adcoch1]

There is factory and home loaded ammo running125 grn at 2300fps, but its blowing primers and splitting cases. 2100fps is a much better target... Just my thoughts.. Brass lasts longer that way too.

 

[LoonWulf]

There is factory and home loaded ammo running125 grn at 2300fps, but its blowing primers and splitting cases. 2100fps is a much better target... Just my thoughts.. Brass lasts longer that way too.

Blown primers were my issue, admittedly i was using (still am since i have them) cci400s, and even some Federal SRPs. Lil' gun is supposedly the powder of choice when looking for velocity with the 125s, its not one i stock tho.

 

[adcoch1]

Same here, h110 is the only one I've tried so far. Still need to order up some of those Missouri Bullet Co heavyweight bullets to try subsonic. So far I only tried a few Sierra 200 grn...

 

[LoonWulf]

Same here, h110 is the only one I've tried so far. Still need to order up some of those Missouri Bullet Co heavyweight bullets to try subsonic. So far I only tried a few Sierra 200 grn...

4-5gr of 231 behind the mbc 245s delivered bout 800-850fps from my 16" American and sounded like .22. Wont even try to cycle a semi tho.

 

[hq]

This is what I had read about the .300 when i built my 16" upper, but i couldnt even come close to x39 much less 30-30 performance from it.

Exactly. This is the common consensus and while it may be possible to match the performance of some x39/.30-30 factory ammo with BO handloads, handloading either of them will reinstate a substantial performance gap.

The BO has one major advantage. It feeds great in an AR from stock mags. So, if building an AR is in order and someone really wants one, go for it. It's also one of the go-to subsonic calibers for people who don't handload so it makes experimenting with suppressors easy.

 

[someguy2800]

There is factory and home loaded ammo running125 grn at 2300fps, but its blowing primers and splitting cases. 2100fps is a much better target... Just my thoughts.. Brass lasts longer that way too.

I had no problem with 125's at 2400 with H110 from my 16" barrel. No pressure signs whatsoever and it was a book load. Factory 7.62x39 ammo all runs about 2400 in my 16" barrel as well. I'm sure that can be improved on.

I really like 300 blackout, its fun to shoot, especially at steel. I switched over to 7.62x39 so I could shoot steel case ammo and not worry about picking them up. If the ammo/brass was not a consideration though I liked the 300 blackout better.

 

[LoonWulf]

I had no problem with 125's at 2400 with H110 from my 16" barrel. No pressure signs whatsoever and it was a book load. Factory 7.62x39 ammo all runs about 2400 in my 16" barrel as well. I'm sure that can be improved on.

I really like 300 blackout, its fun to shoot, especially at steel. I switched over to 7.62x39 so I could shoot steel case ammo and not worry about picking them up. If the ammo/brass was not a consideration though I liked the 300 blackout better.

I checked those loads out, and while i do think you have a very fast barrel, they were within what i would consider safe ranges. I also had another person send me info on a lil gun load that was hitting 2400+.
My own loads went till i blew primers with h110

 

[greg_r]

I like the 300 BLK. But to say it gives you 30-30 performance or 7.52x39 performance is absurd.

The 7.62x39 with comparable weight bullets will be about 100 feet per second faster than the blackout at the muzzle. And while the blk will catch up, the BC thing, by the time it does you have reached the range you really shouldn't be shooting at game with it.

The 30-30 will best the 300 BLK by 400 fps or more using the same bullets. I have been loading the Sierra 135 grain in the 300 BLK and it really performs well, but the velocity is almost exactly what I can get with the 30-30 using a 170 grain bullet. I am pushing the same 135 grain bullet out of my 30-30 Handi Rifle over 2500 fps!

Where the 300 BLK excels in subsonic and short barrels. My 30-30 will not stabalize anything over about 190 grains, my AAC Handi will shoot one hole groups at 50 yards using the 208 grain Hornady pushed by IMR4198 and the 300 BLK is my choice in an AR pistol.

 

[greg_r]

I checked those loads out, and while i do think you have a very fast barrel, they were within what i would consider safe ranges. I also had another person send me info on a lil gun load that was hitting 2400+.
My own loads went till i blew primers with h110

Lil'Gun is indeed one of the fastest powders you can use in the 300 BLK. Probably the fastest powder. But at what cost? Lil'Gun burns hot, due I am told to it's nitroglycerin content.

Lil'Gun gets me almost 2000 fps out of my 16" barrelled 300 blackouts with the 150 grain pulls I like to use for plinking. I also like that the charge weight for the subsonic is 1/2 of what my supersonic loads are. Charge the case once for 208's and twice for 150's.

But there have been problems, not with my MSR's that I can see, but with my 410 loads. Hulls will not last when using Lil'Gun. And while I have not used Lil'Gun in any of my revolvers, reports are many that there have been damage to the forcing cones when using this powder.

Lil'Gun is still my go to powder for my 450 Bushmaster, but I have pretty much quit loading it in anything else. I have about 2 pounds of Lil'Gun left, when it's gone I will be replacing it with H110/W296. The performance is comparible in the 450 Bushmaster, but the velocity loss in the 300 BLK is close to 200 fps!

 

[Theohazard]

I like the 300 BLK. But to say it gives you 30-30 performance or 7.52x39 performance is absurd.

Sorry, I should have been more clear: I simply meant that it fills the nitch of a 7.62x39 or .30-30 in a more convenient package for AR-15 owners. I’m well aware it doesn’t match those two cartridges, but it comes close enough for most people’s purposes.

.300 BO isn’t all that far off from the performance of 7.62x39 with some loads, but you’re right, it doesn’t quite match it. And yes, it loses out even more to the .30-30, but since its bullets usually have a better BC it makes up a little downrange.

 

[Glockula]

The 300 is what it is .It ia not a 30-30 or a 7.62x39 . those looking for that are in for disappointment . It is a fun caliber that doesn't use a whole lot of gun powder and haa easily sourced components. It borders the pistol caliber carbine moving into a rifle caliber.

I love mine but then again I have no illusions of the limitations of the cartridge .Just my $.02