i fitted a optisan eve 4-16x44PI on my air arms s510 R TDR , uncertain what brand the mounts are, long story short, i maxed out on elevation. i started off with both turrets in the centre position. the target was a mere 15 yards away, the POI was well low !!! i've found a set of sportsmatch mounts in my gun cupboard and put them on with a hawke eclipse 30SF 4-16x50IR.