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M4 Feed ramps

Discussion in 'General Firearm Discussion' started by 82nd Infidel, Apr 25, 2012.

  1. 82nd Infidel

    82nd Infidel Gladstone,Or. Member

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    I recently built an AR from quality components and have noticed that if I cycle and eject an unfired round that the bullet shows scratches that appear to be caused by the feed ramps.
    Is this something that smoothes out in time,should I polish it myself?
    This cannot be good for accuracy.
    Anyone else experience this?
    Thanks.
     
  2. ArBrnSnpr

    ArBrnSnpr PNW Active Member

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    I had a similar issue and remedied it by tightly rolling some 600 grit sand paper then lightly sliding it up the ramp in the direction of travel of the round for about 15-20 passes per ramp. After that I took a wool polishing wheel on my dremel and at the lowest speed buffed out the sanding marks with Fitz metal polish. I now no longer get any kind of marring on the jacket of a round after ejecting it.
     
  3. eldbillbo

    eldbillbo clackamas New world samurai and a redneck none the less Bronze Supporter

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    are you using a receiver with feed ramps and a barrel that does not have extended feedramp?

    scaled.php?server=23&filename=m4ramps.jpg

    if yours is like the bad one pictured thats why its happening
     
  4. 82nd Infidel

    82nd Infidel Gladstone,Or. Member

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    Thanks,sounds like an easy fix.
    "All The Way"
     
  5. ArBrnSnpr

    ArBrnSnpr PNW Active Member

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    So easy a leg could do it!
     
  6. Eric911

    Eric911 WA Member

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    The scratches you see are more likely occurring during extraction than feeding. During extraction, the round is under ejector tension and the bullet contacts the back side of the barrel extention.
     
  7. Ding

    Ding Lighter Side of Oz Active Member

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    LMAO airborne all the way.
    Your scratches may come from the magazine lip. Check the mag and then check the feed ramps.Is there any copper or brass on them.You can color the feed ramps and charge a few rounds to see if any of the color is removed.