Re: 338\'s: 250 gr vs300 gr bullets
My brother has a 32" Pacnor barreled 338/378wby which has I think about 5-10gr more capacity than the Lapua Imp and even a little more yet than the regular Lapua. Steve Shelp knows for sure. It will push a 300gr SMK at 3000 fps at between 64,000 and 67,000 psi over the Oehler 43. Which I might mention at this point, was the same load at 118gr of H870 at 4.100 OAL that produced 59,000 psi with virgin brass. It has been loaded 4 times without being annealed and psi has moved up that much. Same powder lot so it is the brass.
Interestingly enough, the original 65,000 psi load of 120gr was grouping at just over 1 MOA and the 118gr load under .7 MOA.
The velocity has raised with the psi too with the work hardened brass by 50fps but it still groups under .7 MOA every time.
Thought some of you might find that interesting.
I would guess that 2800-2900 would be possible in the standard Lapua chamber and another 100fps availible with the Improved version in a 27" tube.