Dented case mouth


November 25, 2007, 04:35 PM
I tried to search, but the search function was returning a blank page... So I'm sorry if this has been asked and answered.

My 556 REALLY ejects cases quite a ways. I mean, it really slings them. It's denting the case mouth on every casing it ejects. Having to buy new brass for every lot will add to my cost quite a bit. Is there a safe way to put those case-mouths back into round?

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November 25, 2007, 04:39 PM
How bad are the dents? When I pick up dented pistol cases, I just size them and load them and the dents get ironed out along the way. If it's a really bad dent and you're afraid it might crease, use an expanding die first, then resize, then expand it again.

First I would try ignoring the dents and see if they go away.

The Bushmaster
November 25, 2007, 04:49 PM
A photo would help, but it sounds like what zxcvbob said. Resize them and load'em. If they are that dented in at the mouth use a tapered drift punch to open them up so the die can deal with them. Even a wooden dowel would do the job...

November 25, 2007, 05:50 PM
I made a tool just for that problem out of the hardened steel core of a .30 caliber armor piercing bullet. I drilled a hole of the right diameter in a steel block and used a set screw to hold it in place, with the pointed end up. I just push the dented case mouth down on the steel core and it straightens it right up.

For .30 caliber case mouths, I drilled another hole in the block to accept the whole armor piercing bullet. It's just right for fixing those dented .30 caliber case mouths.

For larger calibers, I used the core from a .50 BMG armor piercing bullet. The whole rig only takes up about 3" x 3" on my bench, with the steel block being about 1.5" thick.

Hope this helps.


November 25, 2007, 06:40 PM
Hmm... if my deburring tool didn't have the edges on it, it'd be perfect for straightening out those dents. I'll look around for something conical that I can secure to the bench for that. If I don't find some solution, I'm going to be wasting a lot of otherwise perfectly good brass.

November 25, 2007, 07:10 PM
Try a nail-set punch. You don't need to fasten it to the bench.

November 27, 2007, 03:25 AM
Some velcro (fuzzy side) on the upper where the mouth is hitting or on the bulge behind the ejection port may stop most of the denting. Try 6 or so thicknesses of masking tape temporarily to see.

lee n. field
November 27, 2007, 08:42 AM
My 556 REALLY ejects cases quite a ways.

Mini-14 Ranch, or Saiga/AK?

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