300 AAC vs. 7.62X39

**rsilvers** · 03-15-11, 19:19

Allen Arms and others have 300 AAC factory primed brass in stock now. 2000 cases per box. Prices are much lower than 7.62x39 brass.

**shadow65** · 03-15-11, 19:44

CMMG is also carrying the primed brass for 300 now.
http://cmmginc.secure-mall.com/categ...g-Supplies-190

**Turnkey11** · 03-15-11, 20:31

Originally Posted by krichbaum

I like the 300blk cartridge, it has a lot of advantages. But I've decided it just costs too much for me right now. If the ammo price comes down some, and availability goes way up, then I'll reconsider. I'd like to put together a suppressed HD carbine in 300blk, but I know I won't shoot it much (i.e. practice) due to the ammo cost. I'll stick with 5.56 for 'serious' use for now, and I'm slowly gathering parts to build a 9mm AR for a fun suppressed gun.

Im considering building a .300 upper, but dont like the idea of yet another caliber to relaod for. If I do go the blackout route, my goal will be a dedicated suppressed carbine with as a short a barrel as I can reliably run with subsonic reloads.

**TXBob** · 03-16-11, 13:30

One of the criticisms I've seen of the 300BLK is that the rounds are limited in OAL due to the magazine rib in the AR magazine. Do any of the reloaders have expperience with this?

It seems a fine detail that would only arise in certain situations, but when I'm looking at a non-suppressed 300BLK vs 6.8SPC, that would happen to be one!

**rsilvers** · 03-16-11, 13:37

6.8 always needs custom mags.

**TXBob** · 03-16-11, 13:41

Yes, I am aware of that, one of the selling points of 300Blk is it doesn't.

My question was are people finding the claim that the magazine is limiting the OAL of the 300BLK true.

**rsilvers** · 03-16-11, 13:53

For the 110-125 grain bullets I like, it does not limit them because they are short.

It mostly effects heavier bullets - like the 175 Sierra that I use to make major power factor.

**hozer** · 03-18-11, 09:50

Originally Posted by skyugo

anybody roll their own 300 brass out of 223 yet? does it work good?

I have been loading my own for a couple years now. Works fine. Very easy caliber to load for. Kinda like a 30 Carbine.

I load my 300 plinking ammo on a Dillon 1050 and 300 bolt gun ammo on a Dillon 550 with a Prometheus measure.

For supersonic ammo I really like the Nosler 125 Ballistic Tip. For subsonic the Sierra 220 is awesome. For full auto subs I use the 175 Sierra surplus.

In fact the 300 Whisper/Blackout M-16 that Thunderbeast Arms used at their suppressor demo day last weekend used my brass.

The _.__x39 can be tricky to make feed out of an AR due to the taper of the case. I have had 5.45 and 7.62 uppers and neither could go 500 rounds without an issue related to mags and ammo.