221 Fireball from 300 Blackout

[20 Falcon]

Interested to know if anyone has used their PBike, Bullberry, or other forming dies to work 300 Blackout down to 221 Fireball or even further down to 20 Vartarg. Starline brass is generally regarded as an exceptional value combined with quality, and 100 pcs of brass is quite affordable by today’s standards. About the only watch out I have found with it through research is to use caution in load development as the Starline brass is noticeably heavier compared to other Blackout brass makers.

Just curious if anyone has gone down this road. If not, maybe I’ll buy a bag and try it.

 

[L.Sherm]

I think you might run into OAL issues, the BLK brass is gonna be about .070ish shorter than 221 Fireball. You will gain some necking the BLK out brass but not enough.
I think you might be fine in a 20VT though even if you can get to 1.38 ish you will be fine ive ran alot of brass .020 short with no issues.