By: Michael L Karydas

Michael L Karydas — Sun, 24 Apr 2022 19:19:56 +0000

Primer Pocket Crimp Removal for Small Pistol Primers
I think everybody including the manufactures’ have way over thought removing crimps. The idea of using a countersink to bevel the top edge of the primer pocket is effective at removing the crimp but the downside is the lack of control over the depth. The advantage is that beveling does significantly help to reduce or near eliminate flipped primers during priming. The ideal solution is to: 1) lightly bevel the primer pocket to remove the crimp and aid in smoother primer centering and seating 2) have depth control so no excessive material is removed and brass previously processed this way is not affected 3) the sidewall of the primer pocket other than the bevel area is not affected 4) the method is very cost effective and 5) the process is simple and fast.
This is my solution for small pistol primers only. Works best in a drill press.
1) purchase the long narrow step drill bit that ranges in size from 1/8 to 1/2. (Harbor Freight 91616)
2) the only 2 sizes to be concerned with are: 5/32 and 3/16. 1/8 will be ground off.
5/32 is smaller than the primer diameter- it is the pilot and depth gauge. 3/16 step will create the bevel
3) If you can cut a 9mm case in to a cross section this will be very helpful in setting the depth. The average depth of a primer pocket is about 0.120”. If you cannot cut a cross section of a case then slightly drill out the flash hole so you can better see the bottom of the step bit when inserted.
4) The idea here is to grind the 5/32 portion of the step drill so that: 1) the face is flat so not cut the primer pocket when bottomed out and 2) to grind off just enough to get the bevel portion of the 3/16 step to just trim the face rim of the casing removing the crimp and putting a very narrow bevel on the leading edge of the primer pocket.
This is a trial and error at this stage so do not get aggressive with grinding the 5/32 portion. Trim just enough of the 5/32 at this point to get the 3/16 bevel to approach the crimped area. Chuck the bit and test on a casing. Grind a tad off and chuck again. Keep doing so until the bevel is lightly cut. Using an old primer test the how the primer inserts and grind again as necessary. There should be a narrow bevel ring at top of the primer pocket mouth much like cutting a valve seat. It should be the same width as the bevel on the step bit and NOT recessed into the casing.
Tip: If you grind this on a grinding wheel like I did you never get a totally flat face on the bit. So when fine tuning the depth, rotate the bit and find the high edge and lightly touch that against the stone to adjust the depth. This method will produce no marks in the bottom of the primer pocket.
Analyzing the situation: 10-20 minutes
Making the bit: less than 10 minutes
Processing brass: 2-3 seconds in a drill press. Press brass straight up into the bit. You can hold the brass in your hands but I prefer to wear mechanic gloves. Adjust drill press table height to make it a comfortable hand rest.
My bit is designed for 9mm brass because that is all I shoot. All small primers are essentially the same dimensions. I would not go as far as to say that all small primer shell casings have the same depth so you may have to make additional bits for other calibers. The worst case stamps with crimps I have found so far for 9mm are SAR and WIN. These guys always gave me primer issues in the past …. But no more!!! I process all my brass with this method.
Thanks and enjoy
Mike K

By: Guy

Guy — Wed, 04 Feb 2015 20:15:47 +0000

Nice artical. I have the Dillon tool witch is fast and works well. Actually its for sale, hopefully my crimp removing days are over

Comments on: How to Remove Primer Pocket Crimps from Fired Brass

By: Michael L Karydas

By: Guy