80% 9mm 1911 problem

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  • Mark75H

    MD Wear&Carry Instructor
    Industry Partner
    MDS Supporter
    Sep 25, 2011
    17,243
    Outside the Gates
    Rock GI slide, Remsport 9mm ramped barrel, Stealth Arms alloy frame.

    Function is excellent in every way as far as shooting, but its making microscopic brass dust. Becomes evident by choking the firing pin channel and giving light strikes.

    Collected some brass and examined, expecting to find an extractor problem. Basically no mark on the brass around the extractor (20% of brass has a mark at the front where the extractor nose needs to be shortened by stoning), a beautiful ding on 70% 80% of the brass showing where it hits the ejector ... but the entire back of each case is scuffed. No mark on the frame, but a heavy brass residue on the back of the slide, patterning the case and primer, but no motion.

    Timing problem or head spacing problem?

    Arrows are pointing at the dings made by the ejector, showing this is "upright" Extractor marks occur on 20% of them at 4 o'clock as seen this way. Most have no extractor mark, some I can't see the ejector mark, while all show the verticle scuffing.
     

    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,571
    Harford County, Maryland
    I am assuming that is factory ammo and the blunt corner triangle shape on the primers is on the primer during manufacture. If not then there are other issues. .

    Brass in the firing panel is typically from the firing pin hole shaving the case as the case head slides up the breechface during feeding. This indicates a sharp corner on the firing pin hole. The hole needs to be chamfered. A method which works is to use a drill bit several times larger than the hole twisted by hand with the bit centered on the hole. Just a touch to knock off the corner.

    It also looks like there is primer protrusion around the firing pin. This could leave brass as well. During barrel link down the protrusion is sheered off and brass deposited in the firing pin channel. EGW makes another sizer larger firing pin which you could fit to the slide by sizing the firing pin hole to it.

    The difference in the ejector mark on the brass could be caused by a loose ejector, clocking or ill tuned extractor or misformed ejector nose. These can be rectified by refitting (replace if necessary) the ejector, fitting an oversized firing pin stop to the extractor, tuning the extractor, and very lightly filing ejector nose parallel to the case face then polishing it.
     

    Mark75H

    MD Wear&Carry Instructor
    Industry Partner
    MDS Supporter
    Sep 25, 2011
    17,243
    Outside the Gates
    I am assuming that is factory ammo and the blunt corner triangle shape on the primers is on the primer during manufacture. If not then there are other issues. .

    Brass in the firing panel is typically from the firing pin hole shaving the case as the case head slides up the breechface during feeding. This indicates a sharp corner on the firing pin hole. The hole needs to be chamfered. A method which works is to use a drill bit several times larger than the hole twisted by hand with the bit centered on the hole. Just a touch to knock off the corner.

    It also looks like there is primer protrusion around the firing pin. This could leave brass as well. During barrel link down the protrusion is sheered off and brass deposited in the firing pin channel. EGW makes another sizer larger firing pin which you could fit to the slide by sizing the firing pin hole to it.

    The difference in the ejector mark on the brass could be caused by a loose ejector, clocking or ill tuned extractor or misformed ejector nose. These can be rectified by refitting (replace if necessary) the ejector, fitting an oversized firing pin stop to the extractor, tuning the extractor, and very lightly filing ejector nose parallel to the case face then polishing it.

    The primers have a V with a flat bottom.

    The primer on the right is the only one out of 30 that looked like that, so I think it was that particular primer's set in the brass. The mark on the left being different doesn't bother me, it might be the only one like that.

    There is brass dust everywhere inside the gun, not just the firing pin channel ... the brass dust causing light primer strikes is what brought the brass dust to my attention. Its on the slide, the rails, the barrel and the frame ... everywhere fairly evenly.

    A vulcanoed firing pin channel opening doesn't explain the scuff marks on the back of the brass, only popping primers and collecting brass in the channel. None of the primers were popped nor had rings chopped into them indicating a problem with the face at the firing pin channel. I have addressed that in other guns and don't see evidence of it on this one.

    What do you think is causing the scuffing on the right case? (I thought I chose a pic that showed scuffing on both, but you can't see it in the pic. In person they look almost the same as the right one.)
     

    Mark75H

    MD Wear&Carry Instructor
    Industry Partner
    MDS Supporter
    Sep 25, 2011
    17,243
    Outside the Gates
    that is typically the texture of the breech face being impressed into the brass upon firing

    I always polish the breeh face (and varius other areas) on my 1911's with 2,000 grit sandpaper around my pinky finger. That might help.

    I looked closely at the breech face, and it is rough. I am hoping you are correct! :thumbsup:

    I will take this advice! :thumbsup::thumbsup:
     

    Mark75H

    MD Wear&Carry Instructor
    Industry Partner
    MDS Supporter
    Sep 25, 2011
    17,243
    Outside the Gates
    Take a look in your magazine. Maybe the dust is being generated before the round is ever fired.

    Good suggestion. There is an inside brace at the back of the mag that has a sharp cut off top. The mags don't seem to have much brass in them compared to the breech, but I am going to disassemble and polish that edge in each one just because.
     

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