[NWPilgrim]

Military spec brass have a crimp to hold the primer in more tightly. You have to remove it, or swage the pocket to resize it for a proper primer fit. Do not try to seat a primer without reaming or swaging the pocket.

All military brass has crimped primers, as well as many commercial headstamps such as PMC.

My favorite tool for doing hundreds or thousands of cases is the Dillon Super Swage 600. Cost about $98 and is super heavy duty and makes quick work of crimps. Comes with swage head for both .223 and .308/.30-06. This is a bench mount tool.

RCBS makes a pocket swaging die for mounting in a reloading press. I have no experience with this but have heard it may not do as good a job as the Dillon.

The other technique is to use a pocket reamer, not a pocket uniformer. I use a reamer attachment for my L.E. Wilson case trimmer. I think most case trimmers such as Redding, RCBS, Lyman, Hornady have a pocket reamer attachment.

RCBS also makes a pocket reamer attachment for their case trim center. This is an adjustable tool head that indexes off the case head for very uniform pocket reaming, but I have heard good and bad experiences with it. The Dillon swager and the case trimmer attachments usually index off the case web or case length so it is best to have all the brass trimmed to the same length before reaming.

My number one choice if you have a lot of brass would be the Dillon Swager. If you only have occasional crimped pocket brass then get an attachment for your case trimmer. These are usually about $30.