300blk or 6.8

[4tun8]

I've decided to build my next ar but i haven't decided what caliber to build. I already have one chambered in 5.56. This one will be a close quarters (>100 yards) I'm not too familiar with either availibility, price, or efficiency (sp?). My googlefu isn't the greatest. Can anyone point me in the right direction or speak from experience?

[animalmother85]

300 Blackout.












These are all subsonic rounds.

[West Chester]

Another 300 fan here

Same mags and lower as 556. 300 brass can be made from 556 brass and common 308 caliber bullets.

http://300aacblackout.com/

http://en.wikipedia.org/wiki/300_AAC...7.62%C3%9735mm)

[AlpacaFarmer]

BLK with a can....no regrets!

[Clark Kent]

Blackout here. Several shops stock Remington ammo fire it and online I usually find the 115gr rounds for $10 a box of 20. The 220gr subsonics are usually around $20 a box.

[West Chester]

Just put this together to compare #'s 300 vs 556

[Yellowfin]

If you know that all of the shooting you intend to ever do with it is less than 200 yards, then the BLK is going to be more economical in terms of fewer things to buy. 6.8 has a LOT of uses and advantages however such as much more power and availability is sufficiently good, and with 120-140 grain bullets it can have a pretty long reach with the right loads.

[nfafan]

7.62x39.

TacTV just did a comparo the other nite between a DD M4 in 5.56 and 300 - and an AKM.

Bullet drop at 200yds on the 2 .30 cal rounds was dramatic compared to 5.56, OTOH, 7.62x39 went completely thru a cinderblock while 5.56 and .300 only chipped the inside after passing thru one side.

[animalmother85]

7.62x39.

TacTV just did a comparo the other nite between a DD M4 in 5.56 and 300 - and an AKM.

Bullet drop at 200yds on the 2 .30 cal rounds was dramatic compared to 5.56, OTOH, 7.62x39 went completely thru a cinderblock while 5.56 and .300 only chipped the inside after passing thru one side.

I'll do a cinderblock test with some subsonic ammo with the ammo I have shown above in a few weeks. It will not be at 200 yards, but that's not what the OP is looking for, he's looking for 100 meters or less. I'm willing to be the results will be favorable. It has more to do with the bullet design than cartridge design. I'd like to know what type of bullets were used in TacTV's test. If you are comparing match grade bullets to a typical Steel cored FMJ, than yes, the 7.62x39 will have much more penetration.

The other drawback (other than limited bullet selection) for the 7.62x39 is that you now require a different bolt and different non-stanag magazines.

[4tun8]

I'm also looking for compatibility with 5.56 lowers/magazines. I have too many (lol) pmags for 556 and from what I've read, the 300blk uses the same mags, but I can't find if they use their own followers.