Need advice on feeding issue w/ NOE 249gr cast

[miko_a]

Hi guys,

I've been loading and shooting my 300 whispers for years w/ the help of guys here in the forum (many thanks to N310toN170 and alleycat). Used a 175gr OTM loaded with VV N110 w/o a hitch

Last month, I decided to build a 300 AAC/BLK OUT out of curiosity. Was able to complete my build yesterday.

ISSUES:

1. I used my 300 whisper loads (175gr, VV N110, WCC brass) and all the spent shells had crack/s just above the shoulder of the case which i never experienced with my whisper

2. I recently got a NOE 247gr cast which I then resized to 0.309". Also got an Lyman M-expander to avoid shaving lead. Loaded a couple for testing. Did not use crimp on this one, just seated the bullet. Loaded the ammo in the magazine, racked the slide then noted that the bolt did not close. I pulled the charging handle and poof! the unfired shell as well as the powder flew out of the ejection port. had to lightly tap the bullet out of the barrel.

I'm thinking that I should get a factory crimp die? But only a factory crimp die for the 300 BLK OUT is available, would this be okay even if I plan to use cast in my whisper?

Thanks

miko