Barrel Break-in

Discussion in 'The Basics, Starting Out' started by Varmint Hunter, Aug 12, 2004.

  1. Varmint Hunter

    Varmint Hunter Well-Known Member

    Dec 26, 2001
    Breaking in a barrel is like cryo treatment or moly coating; some guys believe that it improves performance while others don't.

    Hart bbl mfg sais it is unnecessary but Lilja bbl mfg feels differently.

    Here is how it is done according to Dan Lilja:

    Break-in Procedure
    For an effective break-in the barrel should be cleaned after every shot for the first 10-12 rounds or until copper fouling stops. Our procedure is to push a cotton patch that is wet with solvent through the barrel. This will remove much of the powder fouling and wet the inside of the barrel with solvent. Next, wet a bronze brush with solvent and stroke the barrel 5-10 times. Follow this by another wet patch and then one dry patch. Now soak the barrel with a strong copper removing solvent until all of the blue mess is removed from the barrel. The copper fouling will be heavy for a few rounds and then taper off quickly in just one or two shots. Once it has stopped or diminished significantly it is time to start shooting 5 shot groups, cleaning after each one. After 25-30 rounds clean at a normal interval of 10-25 rounds. Your barrel is now broken-in.
  2. chris matthews

    chris matthews Well-Known Member

    May 14, 2001
    Do asearch on this topic. I am pretty sure is has been covered in depth before. Our own Iam McMurchy wrote a pretty darn good article a month or so back for American Rifleman covering break-in. maybe he has an extra copy.....
  3. pwd

    pwd New Member

    Apr 24, 2004
    What is meant by this and how is it done??
  4. Mysticplayer

    Mysticplayer Well-Known Member

    Jul 27, 2001
    My take on barrel break in is this. All you are trying to do is smooth out the very last rough spots and burrs in the rifling. You can either use a bullet - as was described in the other posts, or you can manually polish it.

    For any quality BR type hand lapped barrel, I just shoot and clean a bit. They are usually so smooth that fouling stops after a bit of use.

    For production or aftermarket unlapped barrels, I polish with 320grit, JB bore lapping compound and reg. JB.

    The procedure is simply to put some of the 'grit' on an oil soaked cotton patch and run back and forth in an oily bore. You will feel the barrel smooth up. I only run the 320 grit back and forth 20 times or so then clean and check. Repeat if I feel or see rough spots ON TOP of the lands. Machine marks below the surface just don't matter.

    Easy test is to run a dry cotton patch down the bore. Lint will be collected on the burrs.

    I then switch to the red JB. This is like jewellers rouge. A very light abrasive. Go at it for maybe 50 stokes. Things will really start to feel smooth.

    I then switch to reg. JB and go for 50 or so more. The bore will be brilliantly shiny.

    All this takes about 15 min to do and doesn't put any wear on the throat or wallet. I do not polish much in the throat area.

    Barrel is now broken in.

    A bore that copper fouls can still be very accurate. Many of my barrels that shoot tiny groups also show visible green/copper in the bore. Don't get hung up on fouling. Worry about how well it shoots. I do periodically polish with the JB stuff. Eventually, the bore will reduce in fouling but usually never stop.