Crown lapping

Discussion in 'Gunsmithing Forum' started by cpttango30, Feb 7, 2009.

  1. cpttango30

    cpttango30 New Member

    I am looking into rebuilding a rifle I just got. Well the crown of the rifle is a little messed up not a whole lot because the rifle shooting like a dream. I would just like to clean up some of the nicks and burrs on it and others I have. I looked at the one on but this one doesn't look like it will do anything for my crown because it is a rounded crown.

    Is there another system out there that a DIYer could get his hands on for a little bit of money?
  2. LongRifles Inc.

    LongRifles Inc. New Member

    First, check to see if you really need to do it.

    1. Get a Q tip and stick it in the bore from the muzzle end. gently pull it and see if anything catches the fibers. If it does, you have burrs and they should be either machined or lapped out. If the swab comes out the way it went in, just continue to march and leave it be.

    2. If your shooting and kicking an occassional flyer out of your groups this can be caused by a bad crowning job.


    Your bedding might also be junk and/or your ammo isn't tuned to the rifle and/or your scope sucks.

    Nothing is ever simple is it?

    Good luck.

  3. stalkingbear

    stalkingbear Well-Known Member

    Another way of checking the crown after it passes the Q-tip test is to "paint" the crown end of muzzle with regular "White-Out" and fire a few shots after it dries. If the gas escaping is irregular, it needs recrowning.

    Recrowning is actually a 2 step process when done right. First you need to totally redo the actual crown itself by using lathe or a special reamer designed expressly for that purpose. After the muzzle is recrowned, it's time to "break the edge" by hand lapping an inner bevel just slightly. This bevel will transition the rifling to let gas escape uniformly. A good target style crown will enhance accuracy more than is usually assumed. PM me or the other gunsmiths if you have any questions. Neil