I used 158 gr pistol bullets to break-in my 673 in 350 Rem Mag's barrel. They worked very well, the groups were surprisingly good (some under an inch) at 100 yards. I fired about 100 of them before I was happy with the barrel. The loads I used came for the Speer book, I don't remember which number. I will say one thing if you have a chance to try one of these out on an armadillo, it has an explosive effect that I highly recommend!
Good shooting!
Happy New Year!
Marcus.
