Although there may be different schools of thought on barrel break-in, this is what Precision Shooting Magazine recommends:
STEP 1 (repeated 10 times)
- Fire one round
- Push wet patches soaked with a powder solvent through the bore
- Push a brush through the bore (5 times in each direction)
- Push dry patches through the bore (2 times)
- Push wet patches soaked with a copper solvent through the bore
- Push a brush through the bore (5 times in each direction)
- Push dry patches through the bore (2 times)
- Push a patch with 2 drops of oil through the bore
STEP 2 (repeated 5 times)
- Fire a 3 shot group
- Repeat the cleaning procedure from STEP 1 after each group
STEP 3 (repeat 5 times)
- Fire a 5 shot group
- Repeat the cleaning procedure from STEP 1
They recommend the use of a patch with 2 drops of oil after the cleaning so that you are not shooting with a dry bore. It is also advisable to use a powder solvent and copper solvent from the same manufacturer to be sure they are chemically compatible.