View Full Version : Primer Crimp

Tack Driver 1
04-07-2006, 11:15 PM
Hi everyone

I am a new FiveseveN owner. I really like the gun. I noticed the primer crimp on the SS195 and want to know why it is there. Does the crimp make it hard to remove the primer for reloading? Does the cartridge cause that much pressure, that it can blow out the primer?

Thanks for any info and for running a great forum. :) :) :) :machinegu

04-07-2006, 11:34 PM
Welcome to the forum. If you will read throught the reloading section you will probably find the answers to your questions. I don't reload, but a lot of our members do and I'm sure it's probably in there somewhere. :)

revolver shooter
04-08-2006, 12:00 AM
Head space is the reason for the primer crimp, especially in machine guns. All the wear and tear during full auto fire, can cause excessive head space. Since the guns may not be repaired real fast ,the result is that the primer can be pushed out during fire and can jam the gun. The crimp is suppose to keep that from happening.

04-08-2006, 10:37 AM
Exssive head space can at the moment of fire cause the round to move forward in the chamber from the bolt and when the during that time the primer will push it's self out some (because the primer it High Explosive) only a fraction of an inch. When the main powder charge goes up and the bullet contacts the rifling lands it causes tons of pressure in side the chamber and the primer reseats. All the movement cause the primer to just fall out when the shell is ejected.
I have a gun with exsissive head space, it was made wrong. The primers are allways flated after firing. But then when I reload the shells I only neck size themand that fixes the problem.
The crimp doesn't make it any harder to remove the primer.
The crimp has to be removed before you reprime the brass.

Tack Driver 1
04-08-2006, 11:39 AM
How do you remove the crimp for reloading? I have only reloaded 9mm shells before they are pretty easy to reload.

04-08-2006, 12:26 PM
I use a 1/2" Skil drill and a Craftsman X2 Stuck Screw Remover.
Next time I reload 1x fired brass (because all my stuff is here now) think I will try useing my drill press turned on it's side.
That way I don't have to hold the drill and keep the trigger squezzed. Then I will have to find a drill bit, because my drill press only spins one direction.
Faster reloads are better.
I'm also thinking about auto mateing my powder measure so all I have to do is tap a switch to throw a charge.
I alos used a hand powered Layman primer pocket reamer for about 10 rounds. It sucks, I needed something with power to load 100's of 1x fired 5.7's

04-08-2006, 03:28 PM
I use a deburring tool and do it by hand.....I bought a Lee or Lyman tool specially made for removing military crimps....and I still use the deburring tool.

Hey--it works.

Medula Oblongata
04-08-2006, 05:12 PM
The crimp has to be removed before you reprime the brass.

This is absolutely not true. With any other caliber you must remove the crimp before reloading, not with the 5.7x28. The brass is quite soft and a new primer easily fits into the case without removal of the crimp. All of us "old timers" (been reloading the 5.7x29 for almost two years) have noted that cases only last 3-4 firings when the crimp has been removed before the primers fall out during firing, whereas you will get 9-12 of you leave the brass alone.

Here are several links where we have discussed this in detail.



04-08-2006, 07:13 PM
I will try that.
I did blow out some primers today.

04-09-2006, 06:36 AM
I agree with MO, if the primer won't go in at first just rotate the case a little and you will finally find a spot where it will go in.

Also, if you fire very hot loads the primer pocket will stretch anyway and you will still only get a couple of reloads. I have had primers fall out when I removed the case from my press after putting the primer in.

04-09-2006, 09:36 AM
One of my problems is I have to use my press to prime shells, my press only came with the parts to do large primers. I bought it used.

04-09-2006, 10:16 AM

possible solution..suppost to use standard shell holders(as used on your press.

Medula Oblongata
04-09-2006, 01:17 PM
The Lee autoprime ram primer works pretty good, but I don't like to use my press to prime. I bought a RCBS hand help priming tool (uses T shell holders like the press does).

Here is a link for it. I highly recommend this tool, its the best priming tool on the market IMHO.


Here is one with a universal shell holder, but not sure if it fits 5.7x28 (Midway has a great return policy if not)