Custom Rifle Barrel Break-In Procedure

Rifle Barrel Break-In

Nosler Rifle Barrel Image

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 help 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.

Our 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 results in a barrel that shoots better, and is significantly faster and easier to clean over its working life.



Our Model 48 Custom Rifles are fully broken in and accuracy tested prior to shipment, resulting in exceptional out-of-the-box performance and giving you less time at the range and more time in the field.

Pictured Above Model 48 Custom Rifle wtih a Kevlar / Carbon Stock in Obsidian Black, Muzzle Break and a Zeiss HD5 Conquest 3 - 15x42 Lock Plex Scope

Pictured Above Model 48 Custom Rifle wtih a Kevlar / Carbon Stock in Obsidian Black, Muzzle Break and a Zeiss HD5 Conquest 3 - 15x42 Lock Plex Scope



The following procedure is what we recommended when you break in a Nosler Production Rifle:  
(This procedure can be used on other rifles as well)

The Procedure:


Following is the necessarily barrel break-in procedure to ensure reliable and consistent accuracy from your new rifle:

  1. Shoot one round and then clean
    Do this for the first ten rounds.
  2. Shoot three rounds and then clean
    Do this for the next fifteen rounds.

  3. Shoot five rounds and then clean
    then shoot a fouler round
    and then 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.


When cleaning, use these simple instructions:


Use a quality one-piece cleaning rod.
Use a bore guide.
Clean from chamber end only.

  1. Clean powder residue from bore using a solvent like Shooter’s Choice™ or Butch’s Bore Shine™ following instructions on bottle.

  2. Follow with a copper remover like Montana X-Treme™ Copper Killer to remove copper fouling. Instructions on bottle work the best.

  3. 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.

  4. 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. 


Use a stainless Steel bore brush.

Leave strong ammonia cleaning products in your bore for extended periods of time – additionally, 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.



Nosler Production Rifles

- M48 Patriot Rifle
- M48 Outfitter Rifle
- M48 Heritage Rifle

Nosler Custom Rifles

- M48 Custom Rifle
- Nosler Custom Rifle Packages
- NoslerCustom Rifle (NCR)
- Varmageddon AR Rifle



Thinking about a new Custom Rifle?

Custom Rifle Builder Image

Nosler is excited to announce new M48 Rifle Custom Options.  We have added stock options, new cerakote colors and other upgrades and options.

Best of all, the M48 Custom Rifle can now be yours at a starting price of $2495 that is a savings of $1300 over last years price!

Check out our online Rifle Builder application at to view any combination of specified options and features.