Why remove the crimp?

If you keep trying to shove primers into cases without removing the crimp first eventually you will have a primer go off and possibly insert some tiny bits of metal into your body. It will be loud and possibly painful and a heart stopping surprise.

There are many ways to remove a crimp from easy to difficult.

When I first got into reloading I used a sharp knife to remove the crimp (difficult).
Then a chanfering tool, first by hand then by chucking it up in a drill motor (semi difficult). Under power it tended to remove too much metal. https://www.dillonprecision.com/l-e-wilson-case-deburring-tool_8_8_24071.html
I bought a RCBS swaging tool that mounts in a press. It kept bending rods before the crimp was removed.
Eventually I bought a Dillon bench mounted swaging tool. That works great but is rather expensive unless you intend to reload a lot (many thousands) of once-fired crimped cases.
https://www.dillonprecision.com/super-swage-600_8_8_25263.html

mingaa said:

My experience. Someone removed the crimp before the case got to you.
I’ve not seen LC 5.56 take a primer without being swaged, etc.

If it was truly once fired - well, god bless!!!
A military crimp is a strong barrier vs an in coming primer!!

Click to expand...

The brass that I got was literally just picked up from the range and sent to me. The stuff was extremely dirty and I punched out the primers (started to anyway). Nobody removed the crimp as it's still very much there yet.

The type of crimp/staking(sp?) I'm seeing is the ring type. I haven't looked at them all yet but that's all I've seen so far. I've never seen anything like what you Yissnakk shows. For that, I could definitely see a need to do something with the primer pocket. Like I said, the primer I tried went in easily both with the press and by hand.

I have sent an email to these folks I've learned about. Their swage tool seems to be extremely easy and quick to use and pretty cheap too. The only disadvantage when comparing it to the RCBS kit is that is puts pressure on the rim rather than the case head if I understand the mechanics of its function correctly. Improper adjustment can strip the rim but, watching videos of it working, as long as it's adjusted properly there's no danger of that and movement of the lever on the press is very minimal. I'm not entirely sure they're still in business but if you guys are interested I'll let you know if I get a reply.

Environment Test

Here it is in action:


This page has a very informative video of the use of the RCBS kit and shows the different means of crimping/staking:

https://www.midwayusa.com/product/1012920663/rcbs-primer-pocket-swager-combo-2

The brass with the primer shot you've shown is not crimped. It's also why you haven't killed any depriming pins yet.
Here's a quick "primer" on crimping.
The primers are installed then the pocket edge is staked in usually 4 positions. This makes the opening smaller, retaining the primers. So lets think about this for a moment. a larger diameter piece of metal is stuffed in the hole and the hole is closed off around it. That's basic crimping. Now what happens when you deprime? you're taking that oversized piece of metal and shoving it back against and through the crimps. enlarging the hole. Some primers may be just small enough to pass through the expanded crimped hole and seat properly. Others may detonate when attempting to seat them. Removing the crimps is very easy but it's time consuming depending on how many pieces of brass you're resizing the primer pockets on. I have the RCBS Pocket Swage die and it works great. If I'm in a hurry, a countersink bit is used to chamfer the primer pocket to get the crimps out of the way. It's only about 1/2 second per piece of brass, but if you're doing 1000 or so the time adds up.