I am having a problem getting an accurate reload with the 300RUM in a Browning Stainless Stalker. The Remington 180gr Swift Scirroco did a good job, right out of the box (1 1/2" @ 100yds and 3" @ 200yds). I had several boxes of 180gr Grandslam and 180gr Trophy Bonded Bear Claw bullets, so I began loading with those bullets. Once I got up close to the MV of the Scirroco bullets (3250fps), the groups became very erratic with both the Grandslam and the Bear Claw. An "expert" at the range has told me that the stainless barrel will begin to fail within 800 rounds when firing the 300RUM. I have put 400 rounds through the Browning. Anyone concur? Any suggestions?