The primary reason that I sold my Browning Stainless Stalker in 300RUM, was because I figured by time I worked up a load, the bore would be shot out. I have broken in and worked up loads for any number of cartridge/rifle combinations in over 45 years of hunting, reloading and target shooting, and I have never encountered such a finicky piece as that one was. Sure, the concept was excellent, having a non-belted long magnum sounded like a great idea for working up the optimum load for long range game taking. Evidently, from what I have read here, several things come into play, to include:OAL, type of propellant being JUST right, primer and bullet choice, topped off by quick and heavy bore groove clogging. Certainly one has to be aware of these factors in reloading for any high powered cartridge, but with the 300RUM, each factor seemed to me to be excessively critical. I admit, I gave up. I bought a Winchester Ultimate Shadow in 7mmWSM and had a tack driving elk rifle, ready to go, after testing with less then 40 rounds! My experience is no reason for anyone to make any conclusion, regarding the 300RUM, as I only dealt with one rifle in this caliber. However, once burnt........
Steve Ashe