.300 Blackout 175g Sierra Major Load

[spencerhut]

In case anyone else needs this info I worked up a ~324PF load in my 16" .300 Blk yesterday.

19.6g of AA1680

CCI SR Primer

Sierra 175g BTHP

2.210 OAL

R-P, Hornady and AAC cases. The Hornady and AAC cases have primer crimps, the Rem do not.

~1840'ish at 15' from the muzzle

No pressure issues. Primers were a little flat, no more than a M193 / M855 duplicate load with the same primers.

[spencerhut]

I found when mixing in cut off .223/556 cases this load needed to be backed off to 19.2 or so. A 19.6g load in a recycled 5.56 blank case yealds 1920FPS!

[Histate]

I found when mixing in cut off .223/556 cases this load needed to be backed off to 19.2 or so. A 19.6g load in a recycled 5.56 blank case yealds 1920FPS!

What headstamp was the 5.56 case? Was thinking bout loading some 175gr with A5744 using converted LC brass. Hows the drop on the 175gr @ Vel of 1840?

Edited August 5, 2013 by Histate

[spencerhut]

I found when mixing in cut off .223/556 cases this load needed to be backed off to 19.2 or so. A 19.6g load in a recycled 5.56 blank case yealds 1920FPS!

What headstamp was the 5.56 case? Was thinking bout loading some 175gr with A5744 using converted LC brass. Hows the drop on the 175gr @ Vel of 1840?

The 5.56 cases were LC. It falls like a stone > 150 or so. 100y zero = 138y point blank max. 125y zero puts you no more than 2" high 0y to 150y with a drop of 3" at 155y PBM. 10" drop at 200y = hold high chest.2