What in the heck is this?

[Coldfinger]

You need to clean your brass. Also if you are runnimg light loads step it up. Lower charges don't seem to burn as clean sometimes. What powder are you using?

H-380 religiously, sometimes 3031&4064

 

[kfreeze]

H-380 religiously, sometimes 3031&4064

What is your charge weight? I've never had h380 do that in my 22-250. Also are you using magnun primers?

 

[Coldfinger]

Depending on bullet weight 38-40 grains. CCI Br2 or Federal GM match no magnums.