.300 BLK

[SS_N_NE]

A question:
I just started some .300 AAC Blackout reloading. Cutting down .223/5.56 brass and shaping in Lee die set.  The SAMMI case length is 1.368"-.020" in the dimension drawing. Anyone with experience have a good starting case length to allow for reusing the brass after fired?

The long story:
Got a 80% receiver for an AR15 build some time back. Collected parts and finished the receiver a while ago. Finally bought a barrel and committed the build to .300 BLK. Just wanted a .30 rifle and the round has a wide range of options and uses some common brass to chop up. OK...I like to reload almost as much as shoot. Just waiting on a DD RIS carbine rail to show a good price on eBay (yeah...cheap a$$).

[bkoenig]

I have one, although I don't shoot it a lot anymore.  The brass doesn't really stretch much at all - it's almost like handgun brass, with such a minimal shoulder.  I don't think I've ever bothered to trim mine after the initial trim down while forming it.  I just used the Lee trimmer setup, so the cases ended up at whatever length those are set to since they're not adjustable.

I've actually thought about selling my .300 upper and getting a Handi Rifle in the same caliber.  My primary interest in this cartridge is for shooting subsonic suppressed rounds, and the Handi Rifle would be a lot quieter.  AR's have a ton of action noise.  The main reason I haven't is because my wife wants to start deer hunting one of these days and a 10.5" AR in .300 BLK would make a great rifle for her.

[SS_N_NE]

What trim length are you ending up with?

I have the Lee Deluxe Quick Trim case trimmer and the matching BLK die. For those that don't know, this trimmer fits into a reloading press, puts the case in a shell holder, up into a die and has a handle on top to crank the brass to size. The Deluxe has a set of blades that also chamfers the case ID and OD. So the press can be used for trim duty. There is an adjuster collar on the cutter that allows a few thousands reduction in the case length. Right now, with everything set out, I get 1.368" but expect the cases to grow slightly if anything just from re-forming. Guess I will find out.

Seems a lot of people get board with .300 BLK unless going the SBR Surpressor route.  I am more into .45 and 9mm... so this seemed a fun pistol sort of load for a rifle, or turn the rifle into a pistol...lots of options. Would even like to try a Beowulf someday.

[bkoenig]

I'll try to remember to chuck one up in the trimmer and measure it this weekend.  If you don't hear from me in a few days post here again to remind me.