Primer seating

[Chernobyl]

When seating cci250 primers in 1x fired hornady brass, approximately 8 out of 40 did not seat flush or below. They are visibly raised. New to reloading and using a big boss 2 press to set primers. Do the pockets need uniforming or is the big boss press just shitty at seating primers. I have primer cup set properly on press and ram feels consistent with each stroke. Any tips?

 

[pugnado]

Inconsistent brass?
Warped primer pockets? (from shooting too many Bubba's pissin' hot loads?)
Crap left in your primer pockets from the first firing?
Do you have a hand press that you can chuck those things into and see what's what with hand pressure?

 

[Chernobyl]

Brass was Originally factory ammo. Fired and this is firs time I am reloading. I cleaned primer pockets out flat head screw driver. Look pretty clean. I’m thinking press is the issue. Going to buy a hand press and see what happens