After much practice and a shooting clinic I can state that I am much better today at shooting with my scope at 4X than I was when I originally posted. I can now consistently* do mid to upper 80's in the offhand phase on high power competitions which is the same as I did with irons.Absolutely. Magnification not only magnifies the target, but also any movement of the rifle. The less stable the position (offhand is the least), the greater the perceived movement. I can't prove it, but I am convinced the progressive unsteadiness is geometric rather than arithmetic as power goes up - in other words, 9X isn't three times more unstable than 3X, but is closer to thirty times. Anything above 4X and any offhand shooter will spend for more time chasing the reticle than he will actually aiming at the target. It is why I never hunt with the scope set higher than 4X. In Africa particularly, an offhand shot will likely be fairly close and need to be made very quickly. On a really long range reach from a solid rest, one normally has time to crank up power. At shorter ranges it is just the opposite.
Looking back it was the lesser supported positions that gave me the most trouble with offhand being the absolute worst. My seated rapid scores also went down initially but not as much. Scores in prone rapid stayed about the same however prone slow actually went up!
BUT I reiterate, it took a LOT of practice.
*OK so I have good days and bad days.