I’ll throw a monkey wrench into the conversation. 300WSM and 300WM factory 200gr Federal Terminal Ascents state 2810fps on the box. Turns out, that’s out of a 22” barrel. Guys I know are cronographing them at just over 2900fps+ with 24” barrels, and close to 3000fps with 26” barrels. I currently own a semi custom Kimber Classic in 300WSM and a Weatherby Mark V Deluxe in 300WBY. Yes, the WBY is about 100fps faster, but that’s minimal. IMO, the fact that the 300WSM is a short case, and they can be built around smaller guns, just makes them so much nicer to carry in the field than the WBY.
There is something wrong with either your chrono or the Weatherby. I own three of them and with factory or my handloads (189gr) i attain the published velocity of 3250 FPS. That in my view IS significant.
