300BlkTalk

I picked a bad time to finish my 300 AR build just a few months ago.

In a panic, I ordered 500 cases formed from mixed brass.

Since I already had a batch of LC that I started my handloading with, I just now got around to prepping them, and, whoa, case lengths run the gamut from 1.348 to 1.364.

Should I send these back and tell the guy to stick em?

For the 300 AAC Blackout, the MAX case length is 1.368" -0.020". What the tolerance is telling you is that the case may be as short as 1.348" or as long as 1.368" and still be in spec.

If they were mine, I'd sort them by brand and trim them all to 1.348". Check case weights on a scale. Starline brass is 11.2 grains heavier than Hornady brass for example. That has a great impact on your max loads.

Meaning load to the heaviest brass if your making on one load to be used for all cases.

Also, check those headstamps against the Bad Headstamp Sticky on this board...discard all that are on the bad list, check the mouth wall thickness on any you can't find on that list.