300/221 Dies what else will the reload

[53caddy]

So I picked up some wildcat dies that most likely I won't use but one is a 300/221 that I thought after some research that I might use. What I understand the 300/221 is a 300 Whisper. Am I correct in that statement. We'll I am building a 300 Blackout AR currently. Will these dies reload for the 300 blackout?

[BK7saum]

Yes, 300 / 221, 300 whisper, and 300 blackout, are all the same cartridges as far as the case dimensions are concerned.

[GRUMPA]

Those might work for the 300 Blackout with something to keep in mind. The 300 Whisper case length is 1.400 and the 300 Blackout is 1.368 -.02 so if you plan on using the seating die to roll crimp, it might not happen. If I were to use those I would pick up a LEE Factory crimp die in addition to what you currently have.

[53caddy]

Those might work for the 300 Blackout with something to keep in mind. The 300 Whisper case length is 1.400 and the 300 Blackout is 1.368 -.02 so if you plan on using the seating die to roll crimp, it might not happen. If I were to use those I would pick up a LEE Factory crimp die in addition to what you currently have.

Thanks grumpa.

I will plan on getting a lee factory crimp die I usually do for every rifle caliber I reload. Now time to figure out what 339 NNN is.

[bruce drake]

They work for 300BLK. I use 300/221 Fireball RCBS dies to make my 300BLK ammo for an AR.

[reed1911]

Yup. Unless you buy them from JD, they will crimp just fine and re-load just fine. The ones that RCBS, Hornady, and Redding all sell are designed so that you have lots of adjustment in terms of both seating and crimping.

[53caddy]

Yup. Unless you buy them from JD, they will crimp just fine and re-load just fine. The ones that RCBS, Hornady, and Redding all sell are designed so that you have lots of adjustment in terms of both seating and crimping.


I have no clue if they came from JD or not they are redding dies.

[Gelandangan]

IF they are from JD, the set will be called 300 Whisper not 300-221.

[53caddy]

I appreciate all the help guys.