So finally getting closer to actually shooting my Grendel after a very long time in the making , have had some great help from forum people, I?m getting 2 little scratches on the neck , I dropped new empty brass into chamber and closed the bolt on them and then ejected them and they have 2 scratches on the neck , anything I should be worried about ? Should I just shoot it and it will wear in ? It?s a group buy 20? monster barrel . I didn?t polish the chamber or anything maybe I should have ? Thanks for your help .
Looks like the marks you get if the neck is scraped along the back of the barrel extension lugs.
When the case is ejected are the parallel marks on the side closest to the port (the side where the ejector pushes the case against the lugs as it extracts)?
08-29-2019, 03:29 AM (This post was last modified: 08-29-2019, 03:34 AM by Lemonaid.)
I had bad scratches on the brass in my BCA rifle. I thought it was a rough chamber. It was actually from the sharp machined area in the thread extension, mainly the back two parts of the feed ramps.
I found this out partly on my own, and there are some threads here on the forum about it.
A simple test. Take an unmarred case and hand insert it into the chamber all the way in. Use a cleaning rod to pop it out.
If it is unmarked then it's a pretty good bet it's happening when the ejector is pushing the case to the right before it clears the barrel extension.
Dual parallel marks result from the case hitting on the sharp corners where the bolt head engages into the thread extension. You may be able to see brass marks in there where it's rubbing with a flashlight.
If this is what is happening in your firearm, the basic fix is to de-burr the sharp corners and machining marks as explained in past forum posts. http://www.65grendel.com/forum/showthrea...ass+gouges
Klem, I believe so yes ,on one of the pieces of brass I marked it with black marker and made sure the mark was sitting at 9 o?clock and then let the bolt close on it ejected it and the two scratches are roughly at 1 and 2 o?clock
Thanks lemonaid that seems like a good test , I did search the forum but didn?t seem to come across the correct posts on this issue so I figured I?d ask , now I?m wondering how I keep hitting the question mark symbol when it?s not even showing on my phone as I type/ text these messages.
