They were 4.52 through a club mates pellet gauge. Using the same gauge we found the Sniper Lights would not pass through the largest 4.58 hole, which explained why he was getting a sore thumb trying to feed them into his spring guns.
I have tested the Mediums against JSB's and they are now my chosen pellet through my Walther LG300. But like any pellet these days they really need to suit your rifle to get the best out of them and a friends EV was chucking them all over the place the other day and punching tiny groups at 55 yards with JSB's.
"I'm your huckleberry, that's just my game"