AR denting/scratching/deforming brass?

I'm fairly new to rifle reloading and running into an issue. It seems as though my AR is doing a fairly good job of scratching/gouging my brass at some point during the firing cycle.

For starters I'm not sure exactly what my load was for the cases I'll be posting examples of below as I had 70 rounds of 55gr VMAX and 69gr SMK with varying degrees of powder charges. The absolute hottest I went was 25.5gr of CFE223 under the 69gr SMK loaded at 2.250 COAL. I'm shooting out of a Stag Model 3 with a 16' barrel and 1:9 twist.

All of the brass is Federal Lake City that was from XM855 surplus rounds I purchased and fired originally out of the same rifle. All cases were trimmed to 1.75

I'll post images of each of the cases with some questions/comments on each one. I'd love to get everyone's collective thoughts and appreciate any advice.

Case 1: Seems like this might be a case neck split from a bit too hot of a load? While my hottest loads were on the high end of the load data from Hornady and Hodgdon for .223 loads this is a 5.56 chamber and brass so I wouldn't have expected this. Could this be something else?


Case 2: This does not appear to be a split as it doesn't go all the way through the brass. There are quite a few (70% maybe) other cases that have similar "scratches" in about the same area but I'm discarding this one as it seems to be a deeper scratch than the others. Would you do the same or would you reload it?


Case 3: Roughly the same as case 2 but more of a gouge than a scratch. Would you reload this?


Overall is there anything I can do to avoid this type of brass damage? The brass never hits the concrete, I use a brass catcher. I've seen about 100 threads online ranging from "this is normal" to "replace your barrel" to "file your feed ramp" (along with many other possible issues/recommendations) and trying to make sense of it all.

Thanks again all!

FROGO207 said:

How closely did you inspect it before you loaded it? The sizing die could be scratching it either on the inside or the outside and that will weaken it in the same spot every time. I would look at my resized brass next. Or the chamber neck could be oversized. Does it happen to factory brass that you have fired?

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It does appear that factory rounds experience the same thing. That said, I'll check my sizing die as well. Any suggestions on how best to do that?

If the chamber neck is oversized is the answer a brand new barrel?

Thanks all, I'll try those suggestions.

Would you all reload either or both of the last 2 cases in my original post?

243winxb said:

http://s338.photobucket.com/user/joe1944usa/media/2016 Reloading/Typical Gouges_zpseuuifetm.jpg.html
See info under photo and link.

The nick turned in to a burn through. They start out tiny, get reloaded again, then it gets big enough to notice on the next firing.

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Any idea on what the cause or fix was in that example? If my AR is doing this on the first firing (although not nearly as bad as this pics in your post) I won't be able to get more than 1 or 2 loadings out of a case so I'd like to find and fix the culprit

Blue68f100 said:

The scratching on neck is probably due to the locking lugs on the barrel extension nut. I've built all my AR's and de-horned them before I put them into operation. I've corrected a few of my neighbors AR's to keep this from happening. One was cutting the brass so bad it would split on the 2nd reload. They can get scratched in 2 different ways, going in or during extraction. Stick your finger into the extension nut and see if you can feel any sharp edges. Be careful doing this for I got cut one time on a sharp edge. Depending on where they are, you may or may not be able to remove the burr without removing the barrel from the upper receiver. The last one I did I had to remove the barrel since it was putting racing strips on the neck when the case was extracted. I use a Cratex polishing wheels to de-horn with on my Foredom (dremel). Once done you have to do a through cleaning to remove all of the rubber abrasive left behind from the Cratex wheel doing it's thing. I've also seen magazines put scratches on brass too.

The way to find out is paint a round (dummy) with Dykem or a marksalot and put in the magazine. Now mark the orientation, top of the cartridge. Now release the bolt. Extract and check for scratches/gouges. If you have 2 at 3:00, it's most likely happening on extraction. This is one location where I have had to remove the barrel to get access to. Dents on the neck can be eliminated by tuning the extractor.

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Thats exactly what I was looking for - I'll check it out and report back. Thanks!

Hmmmm I haven't loaded any .308 yet but on a hunch I looked at the cases I've been saving and sure enough there are dents/gouges similar to what I'm seeing in my AR15. The AR15 is a Stag 3 and the AR10 is a Windham SRC. Whats the deal? Is this really common or did I get struck by bad luck twice?

Blue68f100 said:

I use the very fine for knocking off the sharp edges. It's a lot easier before the barrel is installed. It can be done with the upper on, but it's a lot harder to get to some places. Normally you can get to the feed area but not the extraction area at 3:00.

On tuning the ejector you have to shorten the spring. This is done with a small cutoff wheel on a dremel type tool. You don't need to take much off like I posted earlier. Normally 1 coil or less does it. Since you can't put it back take small cuts then test. If you take to much off you will not eject your brass clear, and will have to replace the spring.

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Super stupid question here so bear with me, but what sharp edges exactly are you knocking off? The front end of the lugs, or inside the chamber itself?