Thread: Barrel break-in

There is some merit in statements that barrel steel molecules lay in one direction after the machining process.....even in cut rifling the metal is torn away at a microscopic level. I have recently done an experiment with a Krieger 284 barrel 32mm parallel chambered in 7mm SAUM. It had done 653 rounds and started to produce the odd flyer so I cut it back and reversed the chamber. It copper fouled terribly for the first 180 rounds and is coming right now on the target after 200 rounds.

The muzzle end which was then re-chambered was pristine, but the fouling was the full length and in particular the original throat end was the worst as expected. I think this suggests there was some disturbance of the molecular surface from the direction of the original bullet travel.

If that disturbance of the surface is what has happened I would suggest some care is required in the treatment of a new barrel. The Howa recommendations are good advice, and as @zimmer has stated the barrel manufacturers provide their procedures because they care more about their reputation of providing good products than wanting their clients to wear out a barrel quickly so another can be sold