I would guess no more than 50fps loss from 2” less barrel.
I chopped my 458 Lott from 25” to 23” and lost no more than 30fps, this totally surprised me. Average velocity went from 2287fps to 2255fps with Hornady Dangerous Game 500gr DGX.
I never did a velocity average on my own handloads, just worked up till I hit 2250ish and stopped there.
I doubled my money on that rifle when I sold it.
My 375 Weatherby achieves, with a 24” barrel, 3006fps with 260gr Accubonds, 3088fps with 260gr Partitions, 2904fps with 270gr Woodleigh PP’s and 2832fps with Woodleigh 300gr PP’s.
The 260gr load was hard on one brand of brass, so I throttled it back to just over 2900fps recently, it still kills stuff dead, so no major issues with dropping it down a touch.
Cheers.
