Originally Posted by tbrice23
Im ready to load for new Criteron rem-age 7RM. Im thinking that it might be a good idea to break in virgin barrel with the bullet im planning on hunting with because it might conform the throat to the ogive profile of the 168 vld hunting bullets.
Am I correct or should I use cheaper bullets of same weight for break in?
Your throat wont "conform" (change shape) to your bullet's ogive. It is made of much harder steel than your copper or lead core bullets. The idea of the break-in is to smooth out any roughness in the throat or bore and reduce resulting copper fouling.
My approach is to use a reduced load of heavy bullets and slow powder to minimize throat damage as I send my custom barrels to be nitrided. I wouldn't bother doing that with a factory barrel. You can possibly do pressure testing with your selected bullet in conjunction with break-in, but make absolute certain that there is no cleaning product residue left in the bore as it will affect pressure. But if you choose to pressure or accuracy test after break-in, there is no reason not to use the cheapest bullets available.
That said, It might be cheaper just to use your selected bullets if you have to buy a box of cheap break-in bullets and end up with half a box left over. I use leftovers from other loads that I don't use anymore when I can.