The Firing Line Forums - View Single Post - Proper Technique for cutting primer pockets

cobra81 · December 6, 2007, 02:54 PM

Your Lee primer pocket cleaner will not work to remove the crimp. You need a tool known as a primer pocket uniformer.

If you have spent military brass, go ahead and deprime them as usual. Be aware, it is generally tougher to get a military-crimped primer out than a commercial load primer. The primer is held in by the crimp, and will want to use plenty of lube on the case, in a good strong press, and plenty of leverage.

Now that you have the spent primer out, you will notice that a new primer will not fit into the primer pocket...that's because of the crimp put there to hold the old primer. There are several ways to remove this crimp, thus making the case usable for you to reload. One way is to use a "primer pocket uniformer" tool. There are different designs, some are meant to be used only by hand, others can be chucked up in a drill, and others can be inserted into a case-trimming lathe in place of the regular cutter. Or you can swage the crimp out with a different type of tool. In any case, the goal is to remove the crimp so you can re-prime the case with your own primer.

If you're going to do a lot of cases, I recommend a swager, or a uniformer that can be chucked up in a drill, unless carpal tunnel syndrome appeals to you. It requires a lot of repetitive twisting motion for your wrists and forearms to do a lot of cases by hand.

Lee makes a case mouth chamfer tool that will actually work in a pinch....put the pointed end of it into the primer pocket and twist until you have cut enough of the crimp out to seat a new primer. Not a preferred method.

For the record, after de-priming, I use a lathe case trimmer with LE Wilson's primer pocket uniformer to remove the crimp in the Lake City and Greek brass I reload for my M1. Then I clean out the gunk in the primer pocket with a Lee primer pocket cleaner. Next, I use a Lyman flash-hole trimmer to clean up any roughness in the flash-hole. (For some reason, I rarely find much to clean around the flash-hole in the military brass; hardly anything compared to the rough edges I find in brand-new Winchester commercial brass.)

From there, it's on to case-trimming to length, re-priming, charging, and seating. Good to go! Note: If you're going to use the reloaded rounds in a semi-automatic rifle, especially one with a floating firing pin like the M1, be sure to check to make sure you've got all the primers seated flush or below the case head. A "high" primer can cause a slamfire, and ruin your day.

Hope this helps.

December 6, 2007, 02:54 PM	#5
cobra81 Senior Member Join Date: February 18, 2005 Location: Land of Lincoln Posts: 336	Your Lee primer pocket cleaner will not work to remove the crimp. You need a tool known as a primer pocket uniformer. If you have spent military brass, go ahead and deprime them as usual. Be aware, it is generally tougher to get a military-crimped primer out than a commercial load primer. The primer is held in by the crimp, and will want to use plenty of lube on the case, in a good strong press, and plenty of leverage. Now that you have the spent primer out, you will notice that a new primer will not fit into the primer pocket...that's because of the crimp put there to hold the old primer. There are several ways to remove this crimp, thus making the case usable for you to reload. One way is to use a "primer pocket uniformer" tool. There are different designs, some are meant to be used only by hand, others can be chucked up in a drill, and others can be inserted into a case-trimming lathe in place of the regular cutter. Or you can swage the crimp out with a different type of tool. In any case, the goal is to remove the crimp so you can re-prime the case with your own primer. If you're going to do a lot of cases, I recommend a swager, or a uniformer that can be chucked up in a drill, unless carpal tunnel syndrome appeals to you. It requires a lot of repetitive twisting motion for your wrists and forearms to do a lot of cases by hand. Lee makes a case mouth chamfer tool that will actually work in a pinch....put the pointed end of it into the primer pocket and twist until you have cut enough of the crimp out to seat a new primer. Not a preferred method. For the record, after de-priming, I use a lathe case trimmer with LE Wilson's primer pocket uniformer to remove the crimp in the Lake City and Greek brass I reload for my M1. Then I clean out the gunk in the primer pocket with a Lee primer pocket cleaner. Next, I use a Lyman flash-hole trimmer to clean up any roughness in the flash-hole. (For some reason, I rarely find much to clean around the flash-hole in the military brass; hardly anything compared to the rough edges I find in brand-new Winchester commercial brass.) From there, it's on to case-trimming to length, re-priming, charging, and seating. Good to go! Note: If you're going to use the reloaded rounds in a semi-automatic rifle, especially one with a floating firing pin like the M1, be sure to check to make sure you've got all the primers seated flush or below the case head. A "high" primer can cause a slamfire, and ruin your day. Hope this helps.