Forming 300 Whisper / Blackout

1) buy eBay item 141357571908 (or similar)
2) cut .223 Remington brass off just below the shoulder to about 1.380"
3) de-burr case mouth
4) run cases through a Lee .300 AAC Blackout sizing die (Lee # 90575)
5) trim to length & chamfer using Lee 90689 300 AAC Quick Trim Die and 90437 Deluxe Quick Trim Cutter
6) You are now ready to load .300 BLK

HAVE FUN!

Robinson XCR-L Barrel Kits in .300 BLK will be available from Wolverine sometime very soon!
 
i put my 223 cases in my case trimmer to hold them steady and cut them off with a fine tooth hacksaw at the shoulder. they bind and its rough but fast and they come out the sizing die close to final length. i would nevertrim them all the way down its not even a power trimmer
 
budget shooting supply has lots of already made from lake city brass, making it now is pointless
 
I made mine by cutting the neck and shoulder off once fired 223 brass with a small pipe cutter and then FL sizing with Hornady New Dimension dies after spraying them with Dillon case lube. Tumble the brass to remove lube, trim, chamfer and deburr to 1.358" and then use as desired.

No issues feeding / chambering in my Aero Precision barrel but for future processing I plan on getting a mini chop saw and 300 blk case jig (500 cases with a pipe cutter leaves your finger tips feeling like hamburger lol.)
 
I have a 6 inch chop saw from princess auto. I just cut them off at the shoulder, debur, form in the sizing die, trim to length, and a final inside/outside chamfer and load.
I made 700 pieces last time and still have most of them. I only use Remington brass for my 300BLK and it's worked well so far in 4 rifles (still own 3 of them :)).
 
I've got about 5000 223 brass. I watched some youtubes with guys and little chop saws and jigs and I think I will make it a winter project to turn hem into 300BLK brass. I don't have a rifle so chambered, but this will give me an excuse to buy one. :)
 
Gatehouse said:
I've got about 5000 223 brass. I watched some youtubes with guys and little chop saws and jigs and I think I will make it a winter project to turn hem into 300BLK brass. I don't have a rifle so chambered, but this will give me an excuse to buy one. :)
Click to expand...

Get ready for really sore fingers after all that trimming and deburring. lol
 
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