As a barrel maker I have looked in thousands of new and used barrels
with a bore scope and I will tell you that if every one followed the
prescribed break in method A very large number would do more harm than
help. The reason you hear of the help in accuracy is because if you
chamber barrel with a reamer that has a dull throater instead of cutting
clean sharp rifling it smears a burr up on the down wind side of the
rifling. It takes from 1 to 2 hundred rounds to burn this bur out and
the rifle to settle down and shoot its best. Any one who chambers rifle
barrels has tolerances on how dull to let the reamer get and factories
let them go longer than any competent smithe would. Another tidbit to
consider, Take a 300Win Mag. that has a life expectancy of 1000 rounds.
Use 10% of it up with your break in procedure for ever 10 barrels the
barrel maker makes he has to make one more just to take care of the
break in. no wonder barrel makers like to see this. Now when you flame
me on this please include what you think is happening to the inside of
your barrel during the break in that is helping you.
Gale McMillan
NBSRA IBS,FCSA and NRA Life Member