Your primer choice is good but somewhere indexing is awry.
I used a machine to insure alignment ,It was RCBS ,though now the Dillon does it on the press.
The bevel cut ,to remove the crimp,must be centered and equal all around . A hand tool will work
but must be eyeball checked with each use.
As you did not mention the PRESS or loading station I must add the alignment and primer feed is suspect more than the pocket trim
as timing and alignment is critical...even if for a single stage press and I also question RIM DAMAGE if a proper shell plate is in use.
We are blind on this end and must assume all factors that can cause this .. I also doubt that you pocket trim is the issue and suggest a look at primer feed and alignment and indexing (if a moving shell plate or die set is in use.
Is one manufacturer case giving most trouble as I only used FEDERAL,REMINGTON etc ...Well known manufacturers...NO foreign surplus. My ammo load would run at 4000 shells per hour and my DILLON 1050's at 800 or so rounds per hour as it was hand powered.
Check each thing again and don't ASSUME all is correct,for if it was correct,it should be working.
My 40 S&W loader at low speed ,I used 5 of these in different calibers ,in my shop,and 4 Dillon 1050's)
https://drive.google.com/open?id=0B5ZIZLZV4AwIWUswZlNLVGxZLWs