got this from my dead machinist as the last thing he built for me. it's a douglas ss barreled 338 rum. her barrel measures right about 26.25" plus a touch to the beginning of the muzzle brake. 27.5 oal. i used a stoney point oal gauge to measure out a 250 sierra gameking last night, finally after waiting for brass to come in, and i got the bullet just touching the mouth of the neck ! so a bit of adding and subtracting, i came up with a jump of .330 , after seating them at 3.650" ! weatherby's have long throats too, so i called it a 338 weatherby ultra mag ! i loaded up 5 rounds with 95 grains of rldr 25 under the 250 and shot her today... i don't think i need to try anything else...!! after the 3 shot group, i clicked over 7or 8 clicks, since i miss counted due to my friends muzzle blast ! and fired the one just out from the dot. my friend shot the last one.. so i have a question since my chrono is acting up and want a reasonable answer quicker than waiting to go to the range again with his chrono... with the above load and measurements, what do you think my velocity is ? sighted in dead on at 100 yards i counted clicks and have 93 left for distance... should be good to about 1k i hope.