300 AAC BLACKOUT questions

[Prada]

I was looking at the 300 AAC Blackout and wanted to get some input from people here. I'm not so concerned about the subsonic stuff because I can't run suppressed.

It looks like it has similar ballistics to 7.62x39 correct? I'm assuming that it wouldn't be nearly as flat shooting as 5.56\6.8 at longer ranges.

I can see the utility for people that have to run super-quiet suppressed because they can just swap ammo and go from a heavy slow cartridge to a lighter faster cardtridge without changing weapons; but I wondered if it brought anything to the table as far as ballistics, recoil and follow up, especially for SBRs.

Any 300 Whisper\Fireball\300-221 users input would be appreciated as it's nearly the same thing right?

[20X11]

Ballistically similar to 7.63x39, but a much wider range of bullet selection. 300BLK can use almost any .308 from 90 to over 240 gr. 7.62x39 uses .310 pills which are offered in a narrow range of offerings. Recoil is extremely light, so follow up shots are easy. Brass is widely available or can be made from .223/5.56 brass, and all parts except the barrel/muzzle device are the same as the 5.56 AR platform.

Are you looking for someone to talk you into 300BLK? Not many here will talk you out of one.

[Flatliner]

This will not be a popular post but I will say that IF I didn't own suppressors, in spite of the totally correct information posted in the first response, I wouldn't shoot 300 AAC. For a purely supersonic offering, I think there are better choices. The REAL beauty of the cartridge for me comes in that I really do have everything from a pistol caliber carbine replacement to an accurate effective 300-400 yard man/deer killing cartridge in a package barely larger than the aforementioned SMG that is, with some care, mouse fart quiet...

[GunFunZS]

If you want a military style plinking rifle, and you buy ammo, then x39 is a better choice. Cheap commercial x39 is comparable to buying 45ACP. Not ruinous, but not dirt cheap either. Currently per ammo seek the going rate for 300 BO is almost exactly double.

If you make ammo, or you want better performance tailored to any specific purpose, that is easier to do with 300 BO. You also have choice in twist rates. Basically all 7.62x39 guns have the same twist rate which is optimal for a 123 grain ish bullet at moderate supersonic velocities.

So if you want quiet, 300 BO wins. If you reload, or if you want very accurate target ammo 300 BO wins. If you want hunting performance 300 BO wins, and if you want it to be nice in a short gun..... If you want accurate long range, there are better choices than either, but some have made either work.

One advantage not noted above is that 7.62x39 ammo is not optimized for short barrels, and neither are the twist rates. You can get them short, but they are all going to be louder even in super sonic flavor in 7.62x39 simply because they were never really considering performance in short barrels. On the other hand, quite a lot of 300 BO ammo is pretty much optimum at 10" of barrel, or close enough to it that you aren't sacrificing much.

I have a 7.5" 223 barrel, and am in no hurry to put it on an upper, because those things are just obnoxious. 7.62x39 is not as bad, but 300 BO is made to order.

If you are reloading, you can tailor x39 just as you can with 300BO, but brass and projectile choices are limited. So is information. 300 BO is newer, but in some ways it is more thoroughly developed for more purposes.

[Triggerthumb]

Nice write up!!! I'm new to the forum and really enjoy reading stuff like this. The 300 Blackout is a very versatile and actually fun to shoot. Mine is a little Bolt gun, Model seven Remington, it's got nice Timney trigger in it with 16" 1in 7 twist 5R barrel. I've got a couple yotes with it but mainly just for shooting. I've been shooting Hornady 125gr. SST bullets with 18gr.H110 powder. That's the nice part, 18gr. Of powder

[Mike7.62]

Agree with most of the above comments. If you want to run suppressed, the 300 BLK is THE cartridge. If you want to run super, the 7.62x39 has the 300 BLK by a hair, depending upon barrel length, but it has downsides. The two primaries are magazines that actually function reliably, and the bolt face, which is larger than the 300 BLK, and has had a tendency to break. Mine has not yet, but I haven't used it very hard at all. It is easy to replace the bolt, and at $80 bucks it isn't expensive, but it is a downside that the 300 BLK does not have. Ammunition has been covered, and if you handload, is not a problem cost wise or bullet wise, as there are enough .311 bullets in differing weight ranges to keep things interesting.

One of the great advantages that the 300 BLK has is that you can use 5.56 bolts and magazines. The 30 round mags sometimes give problems, but the 20 round mags have not, at least for me. It is also in .308 diameter so there is a much greater bullet selection in both factory loads or handloads. Most bullets of spitzer profile weighing 110 grains or more function fine in the AR, those of lesser weight and more blunt profiles can be problematic. They usually work fine in bolt guns and single shots, and the 85 gr JHP's and 100 gr plinkers can be very quiet indeed, even unsuppressed.

If you are looking for a supersonic only proposition for deer and hog in an AR, you may want to give a look at the 300 HAM'R. It won't work well suppressed, and the inventor, Bill Wilson doesn't claim that it will, but Wilson Combat has barrels for it ranging in price from $249 to $304 depending upon length and profile. I just completed an upper using an 18" tactical hunter profile barrel, and am in the process of working up loads. If you have a 5.56 AR, all you would need is a barrel and a 300 BLK magazine from MagPul, Lancer etc..

I purchased a 10 pack of MagPul 30 round 300 BLK mags from Mag Shack for $112. Starline brass, dies, and loaded ammo are available from Wilson, as is load data if you handload. Wilson's data states that the 300 HAM'R essentially duplicates the .30 WCF (.30-30) ballistically in bullets ranging from 110 gr to 150 gr. I have not shot and chronographed any yet, but John Barsness has in "Handloader" No. 318 of February 2019, and his results match or exceed Wilson's. I am hopeful that my experience will match John Barsness', and to me, it is worth an expense of $400 to find out.

[bangbangping]

If you are looking for a supersonic only proposition for deer and hog in an AR, you may want to give a look at the 300 HAM'R. It won't work well suppressed, and the inventor, Bill Wilson doesn't claim that it will....

I don't understand this. Why in the world would the HAM'R not work well suppressed?

[dellet]

If you are looking for a supersonic only proposition for deer and hog in an AR, you may want to give a look at the 300 HAM'R. It won't work well suppressed, and the inventor, Bill Wilson doesn't claim that it will....

I don't understand this. Why in the world would the HAM'R not work well suppressed?

I’m pretty sure he meant subsonic, although depending on the way it’s gassed, suppressed could also be an issue in short barrels. Same way the large magnum AR style rifle are. Real easy for a suppressed 300 win mag to pull the rim off a case

The Ham’r case/chamber length just doesn’t allow for heavy or really too many long bullets, so you would likely be limited to specialty bullets for subs. There are a few cast in the 165-195 weight range that are short enough to stabilize in 1/11.5 twist so it could be done. There really isn’t a point in a subsonic bullet any lighter, other wise you might as well use a 9mm.

Honestly if someone wanted to push it 3000 fps in a 18-20” barrel with 110 grain bullet is possible. So that’s quite a range of operation. A 1/10 twist and some creative thinking would certainly make that all possible.

[TRshootem]

The 300 Whisper and 300 BLK have always been pretty much subsonic in design and application. Yep, we can do supers in both...bonus. The HAMR, like the Whisper/BLK, appears to be a mod of another round, in this case, the 7.62X40 WT. The design criteria is for a supersonic .30 cal. round in the AR-15 platform. A gun writer close to all this explained the new cartridge and name comes from a similar issue with the 300 BLK . It appears Wilson changed the name to avoid further conflict, though, I have not looked at the prints to note any minor changes. I would buy the Hamr with the understanding it would be a supers hunting rig.

[Mike7.62]

Bangbangping,

Dellet is correct. I did mean subsonic, rather than suppressed. I intend to use my HAM'R suppressed with supers, so my bad in describing the difference.

As to bullet weights etc., yes, longer heavier bullets will not work as the twist in the HAM'R barrel is 1/15". It is meant to optimize bullets in the 110 through 150 gr range, though in my early experiments in checking chambering with dummy rounds made with bullets that I have on hand, some 150 spitzers are too long. The 150 gr Hornady Interlock, both RN and spitzer, and the 150 gr Speer Gold Dot work fine, as do the Sierra and Speer 150 gr FN meant for the .30-30. According to John B's article in "Handloader" his top velocities were 2639 f/s in the 110 (Sierra HP), 2574 f/s in the 125 gr (Sierra Pro Hunter FP), 2619 f/s in the 130gr (Speer Hot-Cor FN), and 2236 f/s in the 150 gr Speer Hot-Cor.

My upper build is an 18" barrel with an intermediate length gas tube. I'm using an adjustable gas block, so damaging brass shouldn't be a factor. I hope.

Anyway, I am hoping to achieve the velocities that are advertised, and the "Handloader" article gives me positive feedback for doing that.