Brass Scratch Fever

**Hawk** · May 5th, 2008, 01:11 PM

(Title stolen from "Cat Scratch Fever")

. I started reloading 223 for my CMP AR15 a week or so ago. Previously I was shooting steel cased Wolf ammo and never noticed the issue I'm having until I switched to brass cases. Every ejected round has 2 parallel scratches running most of the length of the cases necks. A few people I showed this to said it must be scratches or burr's in the portion of the chamber in front of the rifling. I was concerned I damaged the chamber by using cheap steel cased ammo and would have to fix the issue or see a gunsmith or even worse trash the barrel. Yesterday I had some time on my hands and investigated further. First thing I noticed was that if I chambered and ejected a live round, there were no scratches on the neck of the brass, could it be because the case needed to expand and extract before the scratches were made? My second test was to chamber and extract a previously expended round, and to my surprise 2 more scratches were made next to the first 2. So What's the difference? I loaded a brand new live round and ejected it and looked at the round under a magnifying glass and discovered 2 scratches on the bullet this time and not the brass. Are you curious yet? My last test I took a magic marker and colored in the neck of a spent round and marked the side of the round with a line extending the length of the case. I placed the round into the chamber with the line on the case visible through the ejection port for position reference to find out what part of the chamber maybe causing the scratches. Well, they are being created exactly even with the ejection port. So, I'm thinking it's during the ejection process and not in the chamber. I slowly observed a manual ejection and saw the problem. What is happening is the bolt is pulling the case back wards as the ejector is pushing the case sideways (normal). However, as the case clears the chamber the ejector forces the neck of the case across the locking lugs, upon closer inspection of the offending lugs I could see brass remnants collecting on the inside edge of 2 of the lugs. Fantastic! I said it's not my chamber. So, how to solve this problem? I can think of two ways, one reduce the spring pressure of the ejector and or smooth out the sharp edge of the offending lugs. I don't want to mess with the lugs, so I'm going to remove a loop from the ejector spring and see if that works. I'll let you know my results as soon as I can try it. Anyone ever run across this and what did you do to fix it? How about modifying the ejector spring? Any recommendations?

**danws2** · May 5th, 2008, 02:50 PM

It is a common practice to trim the ejector spring on a competition AR. Not for the case scratches that you are seeing, but to control the ejection so your brass doesn't hit the competitor next to you and to make your brass easier to find. After the mod the brass typically ejects a few feet away in the 1-2 o'clock position. Here is a link detailing the modification. You may want to have a spare spring in case you take too much off and you have ejection problems.
http://www.gswagner.com/arejector/arejector.html

Unless the scratches you are seeing are deep I wouldn't worry about them, brass only lasts so long anyway.

**Hawk** · May 5th, 2008, 03:34 PM

Originally Posted by danws2

It is a common practice to trim the ejector spring on a competition AR. Not for the case scratches that you are seeing, but to control the ejection so your brass doesn't hit the competitor next to you and to make your brass easier to find. After the mod the brass typically ejects a few feet away in the 1-2 o'clock position. Here is a link detailing the modification. You may want to have a spare spring in case you take too much off and you have ejection problems.
http://www.gswagner.com/arejector/arejector.html

Unless the scratches you are seeing are deep I wouldn't worry about them, brass only lasts so long anyway.

Thanks, you saved me some time searching for the ejector modification! The scratches are pretty deep, I haven't check to see if they are salvageable yet.

**Hawk** · May 11th, 2008, 07:26 AM

Yesterday, I got the time to cut the ejector spring. I only took off 2 coils with a Dremel cutoff disk. Later that day, I tried it out at the range and I'm no longer getting scratches on the case necks. So my original hypothesis was correct regarding the ejector pressure pressing the brass against the locking lugs on ejection. The secondary benefit to cutting the spring is that now all my brass ends up in a nice little pile about 2 feet to the front right of the ejection port - sweet!