A procedure frequently overlooked by new rifle owners is completing a thorough barrel break-in. When new barrels are made, steel is unevenly stressed and microscopic burs and rough-spots are created. Hand-lapping new barrels certainly helps with those burs and rough-spots, but there is nothing like putting rounds through them to relieve stress and put the final polish on the bore.
Nosler's recommended procedure calls for about 30 rounds and plenty of time spent cleaning the bore, and takes most shooters the better part of a day at the range to complete. However, this hard work ensures reliable and consistent accuracy from your new rifle and results in a barrel that is significantly easier to clean over its working life.
The following procedure is recommended when breaking-in a Nosler Production Rifle, although it can be used on other rifles as well.
- Shoot one round and clean. Do this for the first ten rounds.
- Shoot three rounds and clean. Do this for the next 15 rounds.
- Shoot five rounds and clean.
- Shoot a fouler round.
- Shoot three rounds for accuracy.
NOTE: Allow barrel to cool to ambient temperature before shooting each series of break-in rounds to avoid unnecessary throat erosion. Do not shoot your rifle in succession until the barrel is too hot to touch with a bare hand.
- Clean powder residue from bore using a solvent like Shooter’s Choice™ or Butch’s Bore Shine™ following instructions on bottle.
- Follow with a copper remover like Montana X-Treme™ Copper Killer to remove copper fouling. Instructions on bottle work the best.
- Follow with a second group of patches coated in Shooter’s Choice™, Butch’s Bore Shine™, or similar solvent, then finish with dry patches until all solvent is removed from the bore.
- Finish with a patch lightly coated with gun oil such as Tetra Gun Oil™ or Montana X-Treme Bore Conditioner Accuracy Gun Oil™. Shooting a dry bore will greatly promote copper fouling.
IMPORTANT CLEANING NOTES:
- Use a one-piece cleaning rod.
- Use a bore guide.
- Clean from chamber end only.
- Do not use a stainless steel bore brush.
- Do not leave strong ammonia cleaning products in your bore for extended periods of time.
- Do not allow solvents to contact stock as it can remove the finish.
Once the barrel is broken in, remember to clean the barrel after approximately every 20 to 40 rounds to keep accuracy optimal. A dirty bore is a primary cause of poor accuracy.