What tears up case rims?

[rowdyb]

Doing some reloading of various range pick up brass in 9mm and notice a lot of issues feeding into the shell plate. Looking at the cases they all very dinged up rims. So much so they wouldn't slide into the shell plate without force.

No commonality of head stamps.

What gun or whatever causes this? I've reloaded 90k of 9mm and this is my first time having such persistent issue with something like this. So I'm guessing it is caused by a specific gun or something particular about a gun in general.

Well? I don't sort brass at all, but if I can ID what kind of gun spits this stuff out then I can try not to pick it up if I see it in action.

Thank you.

[Youngeyes]

I don't shoot 9mm, but I've had several guns that extracted so hard that it dinged up the rim pretty heavily. I had a 45acp rifle called a Kriss Vector that did it and the Desert Eagle does it as well. A 9mm SMG would probably do the same. I've never seen 9mm brass at the range from other people's pistols that had that issue.

[Guy Neill]

I wold say there are numerous things that will affect the case rim. Obviously the extractor is acting on the case rim. Depending on the gun set-up, operating pressure may still be hign in some instances, meaning much more force may be required to effect extraction.

The ejector also acts on the rim. The impact of the extractor on the case will vary with the slide velocity. This suggests guns with lightened slides will be harder on brass than those with heavier slides because of the higher slide velocity. A stock 1911 45 Auto slide will have a slide velocity on the order of 25 - 30 fps at the point of full rearward motion.

We are used to faring the ejection port to avoid dinging the case mouth, but that doesn't say the rim doesn't hit against portions of the ejection port.

Magazine feed lips can also mark or score the rims.

There are likely other potential factors that can affect the rims, but those are some that come to mind as possibilities.

Guy

[Steve RA]

One clue might be whether the case rim is bent outward - away from case - or inward -toward case body. Out could be extractor, in the ejector.

[mont1120]

With the move by some shooters to bring the 9MM to major PF, I wonder if the added force required to achieve the PF causes the rims to be subjected to forces they are not normally designed for. As in all manufacturing processes, the cheaper an item is made, the more profit. I am unaware of any 9MM brass designed specifically for this high power factor.

[Postal Bob]

I have that all the time. Most of the dings come from the brass being on the ground, then getting stepped on. At one range we shoot,the ground is all small gravel rock. So all the brass on ground is nicked up to some point, especially after it gets stepped on.

You'll also get nicks in the rim from guns with a very tight extractor, or if the brass hits the ejection port.

Edited February 10, 2015 by Postal Bob

[kneelingatlas]

Case pressure at major PF has more to do with powder/bullet choices than caliber, I load 9 major with soft pistol primers and don't even flatten them. I've loaded tens of thousands of 9 major rounds with whatever brass I pick up and never seen a split case. I have seen what Rowdy is talking about and I suspect it's one particular gun model checking up brass.

[razorfish]

With the move by some shooters to bring the 9MM to major PF, I wonder if the added force required to achieve the PF causes the rims to be subjected to forces they are not normally designed for. As in all manufacturing processes, the cheaper an item is made, the more profit. I am unaware of any 9MM brass designed specifically for this high power factor.

I load and shoot 9 major through an STI. My brass is free of nicks and dings.

Recently I was at the range next to a guy with several fully automatic rifles shooting 9mm. I picked up all his brass (it was A LOT of brass) and upon closer inspection this brass was trashed. Some case rims were heavily dinged to the point of calling them "gashed". Many of the case bases were swollen beyond anything a simple unsupported chamber would cause and the whole batch was covered in grease. I eventually gave up on the batch of brass and tossed it into the recycling bucket.

In my opinion, heavily dinged up brass is caused by firearms that either not adjusted properly or a poor design for anyone wanting to re-use their brass.

[jmorris]

Playing with SMG's is why I bought my first case pro.

[Kaskillo]

Can't tell what is causing what you describe but the Case Pro 100 will take care of it. I am rolling 4k 9mm while I type.

[rowdyb]

I have two 9mm AR's and have reloaded brass I shot with no issue. But they are semi auto, not smg's. I was shooting next to people with two other 9mm AR's a few weeks ago and took all their brass. Of which there was a lot. Now I think I'm regretting that if it is the reason why I have sooo many tore up, dinged up, gouged 9mm cases.

[thermobollocks]

I'd venture a guess that a 9mm AR with too light a buffer or a horked extractor might get some extreme rim damage.

[gm iprod]

I finally got my CasePro I ordered in Jan last this week, ticked every box for the conversion kits. I also picked one up used in 9mm (less than 2000 cases through it) the week before.

[rowdyb]

i don't get how a casepro does anything for the rim.

[Canine582]

funny what Postal Bob said. I shot a IDPA match this past Sat. and noticed that the rounds I picked up were for the most part in good shape. There wasn't any small gravel on the ranges except one. that brass looked like crap, on that range. the other ranges were soft dirt and some mud. that small gravel really works on the cases.

[Postal Bob]

The one range we have matches at, is not only gravel surface, but also concrete walkways throughout(Police firing range). So during a match the brass is stepped on and crunched into the gravel and sidewalks. Many cases have small gravel stuck inside the cases, which you have to pull out first before resizing, or you'll break a decapping pin.