300 blk owners, a question for you...

you know you can load a 308 subsonic right?

Mine shoots about 1 MOA at 100 and even out to three or four hundred but after that it's dropping like a rock. I would say it's a 500 yard max gun unless you can really really compensate for drop. Look up 7.62x39 ballistics info they are pretty close in that respect but way more accurate, but I bet if you handloaded 7.62x39 it would also be very accurate.

Savage has ceased chambering for .300 Blk in boltguns due to inconsistant accuracy.

My 16" 300 BLK AR has been fussy about what it is fed.

155 AMAX's seem to be the best so far with the Speer 125 TNT next. So far, 1" at 100 yards has been an occasional thing with 1.5" to 2" the norm.

5 shots groups are frequently 4 tight shots and a flier.

The rifle does not like the Sierra 125 OTM's that are made for the 300 BLK. 3" and up at 100 yards, factory or hand loads. I hope the bullets work in the M1 Garand.

I have not tried subsonic loads yet. I have components on order.

" Collector0311
300 blk owners, a question for you...
I'd like to hear from some people with experience in different barrel lengths, in regards to long range shooting.
I haven't heard much in the way of the 300blk's ability to shoot at a distance (I understand this is not the focus of this round) however in the search for a 30cal battle rifle with subsonic capabilities, I'd really like to know what I can expect out of a 300blk. Personal experience with different loads would be appreciated! Thanks!"

I can only give one barrel length view.
I have a 16 inch with carbine gas/buffer.

I have loaded several bullets, weights and types. So far I favor the 110gr VMAX and 147gr GI Pulls/150gr SPs.
The 110s are fast and flat (but that goes together doesn't it). They are explosive on target but I feel lack penetration for larger beasts.
The 147gr GI Pulls are cheap to play with. The 150gr SPs are just a slight variation from the 147s and I think are superior for hunting use.

Most have some ballistics program, so I will let you look at the graphs.

I don't load hot loads. My preferred loads run well, lock the bolt back on the last shot.
Velocities are at 10 feet.
110gr - 2300fps
147gr - 1948fps
150gr - 1945fps

My view is that the listed bullet weights are suitable for ranges of 150 to 175 yards for me (the 147 FMJs are not for game animals). Better shots could go farther but I won't.

I don't do suppressed or SBR. However, I have found that my .300 BlackOut loads are noticeably less noisy than my other center fire rifles (and .44 Mag loads). My belief is that I am using powder that is/was normally used in mag pistols with short/er barrels and the 16 inches allows the powder to be fully utilized and not have the blasting concussion.

One of the replys said something about being able to just switch uppers. That's a good idea. I tried that. It didn't last long until I just had to build a lower to match

I hope I helped a little.

collector, as far as a bolt gun goes, savage makes a 7.62x39, as does cz, and I know that zastava makes one on a mini mauser (interarms, charles daly, remington, now century arms is importing than) I know ruger make one at one time as well, and there are probably others. Loaded properly (not wolf) is does pretty well.

Ro1911 said:

Look up 7.62x39 ballistics info they are pretty close in that respect but way more accurate, but I bet if you handloaded 7.62x39 it would also be very accurate.

Click to expand...

Having reloaded 7.62x39, I didn't notice any improvement in groups over Wolf. I was a bit surprised and depressed. Granted, could have been my rifle, which shots "minute of pie plate" at 100 yards. But my groups didn't shrink.. not one bit.

ON the flip side, they also didn't get any worse, and with the costs of 7.62x39 being what they are, I'm pretty glad I stocked up on as much reloading components for it when I did (2004ish). Midway had a sale on .311 124gr bullets in 2000 packs back then and I took advantage of it.

So there's that.

Savage bailed on their 300 BLK offering because their 20" 1:10 twist barrels wouldn't stabilize 220 gr. subsonic rounds.

Most manufacturers are using 1:7 or 1:8 twist barrels. The new HandiRifle uses a 16" 1:7 twist barrel.

Savage was cheaping out by trying to save money using .308 twist barrel blanks, that's why they failed.

Collector0311 said:

Blackhawk - that's interesting, where did you hear that? I'd be interested to read more about their testing and findings. Had wondered about bolt guns in 300blk (like the micro7) and their ability to reach out and touch. I can't for the life of me think of a 7.62x39 bolt gun, and I know the AAC cartridge was designed to mimic it, so I guess I'm not entirely surprised.
Is anyone chambering these in 20" heavy barrels? Would still like to see what kind of accuracy can be had. (not necessarily over 500yds, just grouping from 500 and in.)

Click to expand...

"Some time ago, Savage announced it would be chambering the Model 10 Precision Carbine in 300 AAC Blackout. Since that time, we have tested many variants of this cartridge in various barrel lengths and rates of twist. This exhaustive testing left us quite unsatisfied with the accuracy we were able to get from the subsonic loads in this chambering."

http://www.thetruthaboutguns.com/2012/04/foghorn/savage-scraps-300-blk-rifle/

Others have had better results though.

I've noticed in the rifle mags that when they are doing the blackout that they never bag about group sizes. they tend to just be in a chart and seem to run 1.5 to 2.75 inches at 100 on average, bother super and subs. now, that's usually in an ar, and like 68 says, others have reported better.

I shot my 16 inch at 600 yards with Remington 125 grain match ammunition and hit a 1/2 MOA (3 inch) X ring.

But that is beyond the practical range. 500 yards is the practical outer limit and it is much better within 300 yards.

.300 aac blackout is a low velocity, low BC projectile.. it has the trajectory of a rainbow... 7.62x39 round can use a higher BC and operated at a higher velocity than this will

One of the benefits of the 300 BLK is comparable balistics as the 7.62x39 with comparable bullets from an AR platform. AAC says the 300 BLK will out perform the 7.62x39 at 200 yards.

The low velocity stuff for the 300 BLK comes from the ability for the rifles to handle subsonic rounds. I am sure the 200-220 grain bullets used in the subsonic ronds have a better BC than the light weigh projectiles used in the 7.62x39.

jason41987 said:

.300 aac blackout is a low velocity, low BC projectile.. it has the trajectory of a rainbow... 7.62x39 round can use a higher BC and operated at a higher velocity than this will

Click to expand...

It outperforms any commercial 7.62x39mm ammunition any ranges past 10 yards. By 300 yards, it has about 16% more energy than 7.62x39mm.

As far as "A trajectory of a rainbow" - that is a complete exaggeration. In an M4 the effective range of 550 meters for 5.56mm drops to 450 meters in 300 BLK - not such a big deal considering that it is far superior at closer ranges where shots actually take place.

.300 aac blackout is a low velocity, low BC projectile.. it has the trajectory of a rainbow... 7.62x39 round can use a higher BC and operated at a higher velocity than this will

Click to expand...

The 2 are pretty much ballistic twins though there are many more bullet options in the .308 dia bullet,including high BC's. Believe the BO was intended from the ground as a .30 cal round easily adaptable to the AR platform with no more than a barrel change and to be run subsonic, of which it has succeded in. The downside if it is one would be the cost of the ammo, it will never be as cheap as surplus 7.62 x 39.

It's never going to replace the russian round's popularity that's for sure but it's an alternative to the folks that run the AR platform, me included. My 9" suppressed SBR does everything promised with the 300 Blackout.

I have never been much of an AR guy, but .300 AAC piqued my interest enough that I have started considering the platform. Seems like the best match for the otherwise modular nature of the AR.

Has anyone done much distance shooting with the cartridge? I imagine acceptable accuracy to 200-300yds for a deer or a man, but what level of precision has actually been achieved?

hmm... lets see... 7.62x39mm 123.5 grain, 2,640fps, 1,810 ft/lbs of energy

.300 aac blackout 125 grain, rougly the same ballistics coefficiency 2,215fps at 1,360ft/lbs... yeah, these are soooooo ballistically identicle

do you people just assume that because the actual projectile is roughly the same, that ballistics would be somewhere close?.. its nothing but a slightly glorified .300 whisper

jason41987 said:

hmm... lets see... 7.62x39mm 123.5 grain, 2,640fps, 1,810 ft/lbs of energy

.300 aac blackout 125 grain, rougly the same ballistics coefficiency 2,215fps at 1,360ft/lbs... yeah, these are soooooo ballistically identicle

Click to expand...

I have said this over and over, but here it goes again.

300 BLK ballistics are reported from a 16 inch barrel.

7.62x39mm ballistics are reported from a 20 inch barrel.

This confuses people. I was warned that would happen when I picked a 16 inch barrel as the SAAMI standard for 300 BLK when every other cartridge is a 20 or 24 inch barrel, but thought it was silly to inflate ballistics by using a test barrel length longer than most rifles.

There is no 7.62x39mm ammunition from major company (Winchester, Remington, Hornady, Lapua, etc) which has more energy at past 120 yards than 300 BLK.

Bottom line for me is this, if you are looking for upper swaps, the .300 blk is the way to go. I have the CMMG 16" upper. I like having .30 punch for 300 yards and under. If the preference is farther target engagement switch back to your 5.56.

With my testings, I haven't tried any bullets heavier than 147 and they all have performed well knocking down poppers at 240-265 yards. I like the 300 blk, its the best thing you can do to have .30 power at short/mid range and not have to buy new mags, bolts, or lowers.

As far as functionality, I have about 600 rounds through my 300 blk upper now and it has never jammed or malfunctioned with about 6 types of ammo. (Atlanta Arms, PNW Arms, Gunn, Remington, Hornady, and HSM)

Ammo manufacturer friend of mine is trying to reincarnate the 6.5/223, for AR conversions. He claims 2800 fps out of a 16" barrel, with a 100 gr. bullet. I'm doing to do some chrony work with him soon and see for myself.

rsilvers said:

I have said this over and over, but here it goes again.

300 BLK ballistics are reported from a 16 inch barrel.

7.62x39mm ballistics are reported from a 20 inch barrel.

This confuses people. I was warned that would happen when I picked a 16 inch barrel as the SAAMI standard for 300 BLK when every other cartridge is a 20 or 24 inch barrel, but thought it was silly to inflate ballistics by using a test barrel length longer than most rifles.

There is no 7.62x39mm ammunition from major company (Winchester, Remington, Hornady, Lapua, etc) which has more energy at past 120 yards than 300 BLK.

Click to expand...

actually, those numbers i just gave you on the x39 was from a 16" barrel as well

hentown said:

Ammo manufacturer friend of mine is trying to reincarnate the 6.5/223, for AR conversions. He claims 2800 fps out of a 16" barrel, with a 100 gr. bullet. I'm doing to do some chrony work with him soon and see for myself.

Click to expand...

if you can confirm this, id be interested too.. but it seems you would need some fairly high pressures for this to work at those velocities... even at 100 grains the 6.5 offers a ballistic coefficiency of .390, but this is approaching 6.5 grendel performance and i dont think the 5.56mm has the case capacity for that