if you are shooting airguns or rimmies at long ranges spotting your shots can be hard. first off the holes made by airgun pellets are usually small and hard to spot. secondly most airgun pellets do not retain much energy as to signal an impact. yes FAC do retain energy however when i tried 30ft/lb version at 100+ the impact on stone is not very visible. if you are aiming at metal plates this is not much of a corcern as the hit on white is usually visible.

there are alot of scopes with high mag out there however i found most of them to be somewhat poor at over 18x and i dont like much mag, usually more than 14 is not for me. since i got the menace i like to keep it on 10x because the reticle is calibrated at such. However i do find it hard to spot the shots. So i use a spotting scope.

now i still don't have a mk4 spotting scope with mildot reticle or TMR so how do you tell accurately how much you are off. well here is a good procedure i use and this might recall how the military used the m144 spotting scope even though it had no reticle in it. it is not as good as the modern leupold spotting scope with reticle but here's how to use it.
so imagine we are shooting at 100yards, far away for some..well we place a target that is 8"x8".
this doesn't mean much and many always try to use inches or feet to direct someone on target.. well that is not good enough. a better way is to know the size of target in MOA or Mils(since your turrets are in these increments)

so 8x8" target at 100yards is 8MOA, at 200yards its 4MOA etc. so we take a shot and we hit twice the size of the target and to the right. So we have to tell the shooter to "correct left" we know that if the target is 8MOA at 100yards, edge to center is 4MOA. if we hit twice the size of the target to the right we are 8MOA off(size of target) + 4MOA to get to the center of target. in this case we would have to adjust 12moa LEFT Windage(always dial into the wind). if you want to adjust in mils and hold off divide 12/3.45 = 3.5Mils. if you miss by far as in this case, dial in and dont hold off.

the important thing in this exercise is to know the size of target or the range.

If you dont know the size of target you can find it out by inverting the range finding formula.
size of target in inches x 27.778/ size in mils = Range
Eg
Size of target = range x size of target in Mils (bracketed in reticle)/27.778

once you know the size of target you can use it to correct. remember a 1 foot off at 100 is 12MOA at 200 its 6MOA etc.

hope this helps you in correcting your shots and get on target with the second shot.
please let me know if you do find it helpful, i am trying to get more people into the sport with a better approach to long range shooting.