7.62x39 vs 300blackout

[amoebicmagician]

It seems like more people prefer the 300blk in the ar platform and the fact they can use a 5.56 mag is a big plus considering I have a bunch of them already. How many 300blk rounds can you usually get in a 30rd 5.56 mag?

they say 30, but it's almost always 28 for some reason, although that doesn't seem to make sense since the base of the round is the same circumference

 

[swinokur]

Engage in Rockville will build you a nice one.

 

[amoebicmagician]

I'm a big fan of the 7.62x39 uppers/bolts

7.62x39 has an unearned reputation for being inherently inaccurate, this is not the case at all in my experience when shooting it from an accurate rifle with good quality ammunition.

It doesn't take much to convert, you can just by an upper and bolt, or an upper that includes a boltcarrier and you're gtg

mags work fine in my experience so long as you're not using the ones that are literally an ak mag body spot welded to an AR-15 magazine interface area. There are many good quality reliably mag vendors out there, just do your homework and you're golden.

The best groups I have so far through my upper are actually with yugo surplus, but I don't shoot it often because it's mildly corrosive and scrubbing out the inside of the gas tube is a complete pain in the frakking ash.

Gets decent groups with steel case, Golden Tiger being the best by a decent margin

 

[iH8DemLibz]

they say 30, but it's almost always 28 for some reason, although that doesn't seem to make sense since the base of the round is the same circumference

28 here too.

I think the larger bullets end up touching a bit as they form an arch in the magazine and the bits add up to 2 less rounds.

Also, the forward indentation on an AR15 magazine is designed to clear the neck of a 223/556 case.

308 bullets comes into contact with that indentation and each other. Causing the cases to separate a bit and, again, the bits add up.

 

[amoebicmagician]

holy shit, you're right.

I just took out my mag to fiddle, and you are ABSOLUTELY right, the projectile comes into contact with that ridge in my Pmag as well as the projectiles of the other rounds.

A+ investigative journalism!

This had been bugging me forever

 

[iH8DemLibz]

holy shit, you're right.

I just took out my mag to fiddle, and you are ABSOLUTELY right, the projectile comes into contact with that ridge in my Pmag as well as the projectiles of the other rounds.

A+ investigative journalism!

This had been bugging me forever

 

[Fiddlersgreen]

I think I could live with 28 instead of 30. Overseas it wasn't uncommon for us to only do 28 5.56 rounds anyway

 

[ktigerJ]

I was faced with the same thing a while back and went 7.62x39. The first 5 C Products Mags I got were horrible. The bullet would catch on the dents. The jackets would catch on the housing. You name it I did it to modify the things but it didn't work. New followers all greased up. Dremel'd out the lips. New AK47 Mag springs. Nothing would work. C Products released their Gen II mags and they work great. Feeds whatever you want to throw in there. As in my other post here are the mags I have and have ran about 500 rounds through each one I have.

 

[smdub]

how do you tell (by looking at them) if they are Gen 2?

 

[BradMacc82]

300BLK ran just fine in my pmag's, full 30 rounds.

Your OAL and the condition of the magazines is going to play the largest factor there.

If they're brand new or lightly used mags - the ridge is going to be more pronounced and cause issues when running subs or long OAL rounds.

My new ones, the ridge was very pronounced - if I loaded subs to magazine length, then 28. If loaded to just under magazine length, 30.

The used ones, not as picky.

 

[ktigerJ]

how do you tell (by looking at them) if they are Gen 2?

I was trying to get a photo of them side by side of the ones I have. I can't get it lit well enough though. It's easier to have them in hand as the feel is different. Gen I feels rougher. Gen II feels smother. Gen I ones, that I have, are a gray hue. Gen II are a shiny black. The front lip is a little deeper on the Gen II. I believe this was due to the case getting hung up on the Gen I lips. The back lips look the same. I'll try and get some pics up as soon as I can of the two I have.

 

[DutchV]

I'm somewhat concerned that more Russian imports might be cut off, which could restrict 7.62x39 ammo. Sure, you could still get Hornady, but that's not cheap.

7.62x39 AR bolts and magazines are harder to find than the standard ones.

If you reload, 300 Blackout wins by a mile. Not many people are reloading AK ammo.

 

[ktigerJ]

I'm somewhat concerned that more Russian imports might be cut off, which could restrict 7.62x39 ammo. Sure, you could still get Hornady, but that's not cheap.

7.62x39 AR bolts and magazines are harder to find than the standard ones.

If you reload, 300 Blackout wins by a mile. Not many people are reloading AK ammo.

It's a good point on the reloading and 7.62x39 ammo. It's been a while since i've had to buy any.

 

[Scott7891]

I'm somewhat concerned that more Russian imports might be cut off, which could restrict 7.62x39 ammo. Sure, you could still get Hornady, but that's not cheap.

-Romania and Hungary still make steel-cased 7.62x39 and are importing here (Red Army Standard steel-cased is Romanian, MFS is Hungarian)

-Winchester, Federal, Remington all make 7.62x39 albeit expensive

-Prvi Partizan, Fiocchi, Igman, PMC, S&B all import 7.62x39 but they cost roughly the same as the domestic manufacturers being all brass-cased too

 

[amoebicmagician]

it's not too hard to reload even steel cased 7.62x39. The biggest obstacles are depriming (hydraulic pressure-home depot screw drivers work well for this), friction during resizing (extra or better case lube), and finally the need for specialized primers.

This last can be solved by buying berdan primers, but it is not too hard to use boxer primers, all one need do is remove the anvil from the primer and the build in anvil in the case will do the job instead. I always use some cyanoacrylate just to cement the primers in place just as a precaution, but I think you'd be fine without it. It's mainly to differentiate my reloaded ammo from regular ammo, which usually has a different color primer anyways.

 

[Indiana Jones]

Yea, .300 black is an ok suppressed round for super close. Other than that it is useless. The 7.62 x39 is what I would go with for the reason alone that .300 blk will soon be the next extinct AR caliber.

 

[Fox123]

Dunno I would call 150gr .308 moving along at 2000 FPS useless, but what ever floats your boat.

Strangely enough, quick messing around on hodgdons website, shows velocities and weights to be pretty much on par with each other....

What is it that the 7.62x39 can do which in your opinion the 300BO comes up short?

 

[Klunatic]

Yea, .300 black is an ok suppressed round for super close. Other than that it is useless. The 7.62 x39 is what I would go with for the reason alone that .300 blk will soon be the next extinct AR caliber.

300BLK works fine for me

100 yard Shot



75 & 145 yard Shot

 

[DutchV]

Not only are 300 Blackout ballistics similar to the AK round, they can be obtained from an 8 inch barrel. That makes an AR pistol very useful.

 

[itsslow98]

Just built a 300BLk 12.5" Ar for deer hunting. Threw a spare .223 BCG and charging handle on a PSA upper and had at it. Loaded up the 5.56 Pmag with 20 rounds and had a 3" group at 100 yards with a $39 red dot from walmart. Meets all of the speed and energy requirements for deer hunting in MD and have absolute faith it is more then enough to kill a deer.

300blk is not going anywhere. Only thing is you wont be able to go to walmart and buy a box like you can 7.62.