Strange indeed. Some rifles are just mysteries. I have a tang safety Model 77 in .338 that would not shoot 250 gr. NP's over 2550 fps. Jim Carmichael touted the 68 gr. load of H4350 as good for 2700 fps in the .338. I couldnt make it happen. Started at 65 gr. and worked up to 68, no pressure signs, chrono said 2550. The truly mysterious thing then is that I worked up a grain at a time to 71 grains when the primers started to flatten a little. No change in velocity--2550. So I changed bullets to the 210 NP and right off the top got 2910, just as the book said I should. Then loaded up the new 225 NP (this was in the early 90's and no loading data had yet been published for the bullet) and worked up to 72 gr. with 2830 fps on the chrono and no pressure signs. All loads were at or under an inch and a half. Why would a barrel shoot two lighter bullets to predicted or at least reasonably fast velocities, but not budge past 2550 with a 250 NP? Cartridge OAL was the same on all three bullets. All I could figure was that it must have something to do with the long bearing area of the heavier bullet in this particular barrel. Whatever, I gave up on the 250's and was perfectly happy with the 225's for the next 20 years. Some mysteries are not worth the effort to solve.
