Chuck - you are right - some barrels will deliver up to 150fps higher velocties than another seemingly identical rifle, with virtually the same pressures - why this happens, no one knows. I've had a few of these myself, but some of the mid and low spectirm barrels as well.
; I had one 'low' barrel, a M30 Remington P-17 sporter that delivered 120fps lower speeds than any manual said for any given maximum load - don't know why and of all things, pressure signs were at the max as well. I re-chambered it to .300 WinMag, hoping to get .300H&H factory ballistics out of this 'slow' barrel. Subsequent testing proved the re-chamber, which only moved the throat forward a small amount & turned a slow-poke into a screamer. With some book loads, it delivered over 150fps higher speeds at normal pressures than what those same books showed. It beat the ballistics of the .300WTBY quite easily with some bullets weights - and from a 24" barreled, originaly 'slow' barrel. Sometimes there are no explanations for these 'happenings'.
; 9.3x57 - good shooting! Most vivid lesson, too. Obviously you have too much spare time on your hands - HA! Just goes to show that 'good' practise if of paramount importance.
: So many guys I see each early fall, put up a target at 100 meters and blast away 1/2 a box of Ultra mags, hit the target a few times, then think they are ready for hunting and fully capable of hitting a moose, deer or elk in the heart at 700 yards because some advertizement said they could. Makes me sick at the heart.