We've had trouble at 900 yrds at Bisley with No.4T's on a very hot day, on the bloody new electronic targets, as with no human marker in the butts the spotters couldn't see jack through the heat haze, and we have no idea where the rounds were going, so gave up.
Means we are limited to booking our long range club shoots when we can book a human marking on the remaining non-leccy targets as those of us old gits with old milsurp rifles are at a disadvantage to those with target rifles.
Longest WW2 sniper kill must be Matthaus Hetzenauer's 1200 yrds with a K98kwith 6x scope with BDC only adjustment.