Many moons ago, the Arnold Trail Sportsman's Association in Sidney, ME, used to hold turkey shoots at 100 yards. I never shot offhand, since it was mainly hunters that would do so and I didn't want to beat them with my very accurate rifle, so I shot prone, over a log. One day, they didn't have enough shooters to pay for the turkey, so they asked me to shoot offhand, so I signed up.
Well, as I stood on the line, aiming, the crosshairs were moving around quite a bit, but as they came down to the center, I squeezed one off. They asked me how I did and I said that it looked pretty darned good. When we went down to check the targets, mine was a pinwheel! I'd never even had one shooting prone before, but they never asked me to shoot offhand again.