I tried the Falcon Menace 4-14x44 ffp scope many years ago, I really liked it as a sniper scope setting the px for each shot, when I tried to use it on a fixed px setting it suffered really bad error as little as 10 yards away form the px setting. eg, with it set at 30y it would not group at 40y, set the px at 40y to shoot 40y and it was brilliant.
For hft I settled on the Night force NSX 2.5-10x24. which has closer to no px error than any scope I have ever come across.
The exit pupil dia of a scope is the area that when you eye is within it you will have a full sight picture, the further away from the centre of the exit pupil your eye is the greater the error. The exit pupil size is the objective lens size divided by the magnification so my NF scope has a 2.4mm exit pupil where the Falcons will be 4.4mm on 10x mag giving a lot more room to induce error.
As Steve said in an earlier post, if your eye is central you wont suffer any error, but very often a forced positional shot in hft can induce an error, and if you are not extremely aware it is easy to loose points because of it.
HFT, for people with only 2 buttucks!
VooDoo TwoTwo The next chapter.