I’m one of those nut cases that break in rifles with heavy barrels that are going to be used for target.
It’s a long process and probably does little to help. It’s not going to make a bad barrel good and can (if done wrong) destroy a good barrel.
The best way to test new loads with a new hand gun is to shoot it. That’s one of the great things about reloading, just one more reason to put more down range.
"The difference between stupidity and genius is that genius has its limits" Albert Einstine