Re: .338 velocity for different barrel length
It is really hard to say as not all barrels are equal but I would not expect even 40fps in a truly equal barrel. I shoot a very mild 89.0 grain load of h1000 with 300grn in my edge with a 24" savage factory barrel and it nets a verified 2781fps. I can run 2850fps if I load it up to 92 grains. Between those longer lengths in that bore size, The difference will be very little.