Lee 312-155 and the 300 BO AR upper

[bruce drake]

Odds are its the converted brass if the majority of your reloads functioned at those bullet diameters and seating depths. It makes a for a fun and easy load for 1-8" twist 300BLK rifles once you get the kinks ironed out.

[sixgunner452]

bruce drake, I believe you are correct. I will do some measurements tomorrow. I also have a 1 in 8'' 300 BO. But, mine is a 10.5" pistol barrel. Randy.

[WinchesterM1]

I’ve got some NOE molds, if you would like to try some out before you get a mold, I’ve got a 310-130SP and a 225 round nose

[sixgunner452]

WinchesterM1, Thanks for the gracious offer. I PMed you.

[sixgunner452]

Gentlemen, I did some measurements today. The board members guessed correctly. My cases outside daimeter at the neck are large. Here are the measurement.....

300 BO case measurement result's

Factory G&L 300 BO cases - resized - before loading
.325” to .326” outside diameter

Unfired loaded cases that would not fully chamber
G&L Coverted cases / #1 – outside dia .335” / #2 – outside dia .337” indside AVG – 10 to .11 thou

So. If I understand correctly. Some of my converted cases OD is too large. The inside Diameter seem 2 be OK>

Toss, or turn necks of offending cases. Thanks, Randy

[sixgunner452]

Brownell's sent update. Powder has shipped, has track number.