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Thread: Scored or machining marks on the chamber face. Help !

  1. #1
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    Scored or machining marks on the chamber face. Help !

    I was in the process of cleaning my LMT and I noticed 2 scores or machining marks on the face of the chamber opposite LMT’s “star” Proof mark. I am not sure if these where there before or if I could have possibly caused them. I usually use a chamber brush (the kind that comes in the USGI kit) followed by a few passes with a Boresnake followed by a Otis cleaning kit to clean the barrel and chamber. The only possibility I can think of is the chamber brushed caused it unless they where always there. Do you guys think they will have any adverse affects on the rifle? I am going to try to get a few pictures of the marks

    Thanks
    Last edited by cyclesteel; 07-26-10 at 22:29.

  2. #2
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    There's no way cleaning would score a chrome lined chamber face.... unless you were using an air hammer or some chit!

    A pic, of course, would be helpful.

  3. #3
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    No air hammer here.

    I attached a few pictures. I did not finish cleaning so do not mind the dirty chamber. Any Ideas?

    I did have some issues when I first bought the rifle where the ejector was to a tad too long and I was having lots of FTE . Gun went back LMT and they replaced the bolt. Could any of those malfunctions have caused it . Here is my old thread https://www.m4carbine.net/showthread.php?t=46166






  4. #4
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    Enclose your photos in an e-mail to LMT and see what they have to say. I do not believe the marks would hinder function, but that is not the point. Give them a chance to respond.

  5. #5
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    That looks like where the ejector would be positioned and rotated. I would say that an over-length ejector might have done that with repeated bolt closing cycles. See what LMT says though.

  6. #6
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    indeed.. that's where the extractor would hit, if it was too long. i think that's your answer.

    that aint gonna hurt anything, though.. i wouldn't waste the time on the email.

  7. #7
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    Thanks for the info guys. I seem to have had some odd issues with this rifle. It has been running pretty good since I got it back in January and as long as it will not affect the function or safety of the rifle I am not too worried. I did end up emailing Gene at LMT anyway just to see what he as to say.

  8. #8
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    look at the face of the bolt and front of extractor for matching wear pattern

  9. #9
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    Quote Originally Posted by CAVDOC View Post
    look at the face of the bolt and front of extractor for matching wear pattern
    This... If there's no sign of peening there, I'd just watch it for a while.

  10. #10
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    Quote Originally Posted by bkb0000 View Post
    indeed.. that's where the extractor would hit, if it was too long. i think that's your answer.
    Sounds right. It even matches the bucktooth marks on the snap cap when you tested with it in the other thread. Looks like your old bolt with the out of spec extractor put some buck-tooth marks on your chamber face.

    I'll echo the rest and say contact LMT. If you can, pull up the old RMA number, or information from the previous call, and let them know they are vaguely related.

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