Air Arms Owners Club

this is in my mamba pro 2 5-30x50 manual...

SHIMMING.

ideally your scope should be zeroed to your rifle as near to the middle of it's adjustment range as possible, on some rifles to achieve this it is necessary to 'shim' the lower cradle of the rear (or front)mount using a thin sliver of silver foil, this can be folded for extra adjustment, but it should not exceed 0.3mm thickness to avoid damaging the scope.
i checked both turret's as advised & they are in the mid point positions as it left the factory

i've never bothered doing this before, i've fitted the scope then zeroed it in with the turret's.

the POI on 10 shot's were 2 and a half inches LOW, about 64mm.this was at 15 yard's as in the manual.

would you shim the rear mount or not bother !!!

they state if it's firing low you need to shim the cradle of the rear mount.

are you trying to zero for 15 yards. if you are shooting out to 30 yards the poi will not be as great. if you are zeroing at 15 yards then yes i would shim the rear mount. where did you get the 0.3mm shim advise from? i have used sportsmatch adjustable mounts where there is approx 1.5mm adjustment. 0.3mm is 300 microns which is not a huge amount. a lot depends on how far your scope is mounted above the barrel center to center. in field target we tend to have a larger distance between these two points, more shimming would be required here. if you are running as close to the barrel as possible less would needed, as the center line between the two points is less.

they state zero at 15 yards,then adjust the scope at your desired zero range, if it's out by a fair bit,then shim the scope,to high the front mount, to low the rear mount.i've never bothered previously.,when all sighted in put your turret's to zero.

sounds strange. zero at a distance you don't want to, then re zero? just zero at the distance you wish. if i can achieve a fairly central on the turrets i will. if i zeroed and found that i was a few turns up on the elevation turret, i would shim. the center is the best bit of the glass, and the springs which the turret puts pressure on will be under less stress. in ft we zero at all ranges, but i set my initial zero at 30 yards as it is at the top of my tradjectory curve, this means i only dial upward, and it's just over half way of our max shooting distance of 55 yards.