It only makes sense that it is a problem with the mechanics of your shot. Think about it there is nothing different in the way your bow shoots at different distances, it doesn't know the difference in 40 and 50. So it must be a psychological hang up of yours, I know if I get to thinking about a shot too much I am going to flinch or something. But after all a 50 yrd. shot is just a 10 yd. continuation of a 40 yd. shot. That being said the farther your arrow travels the more evident your mistakes are, at 20 yds. your arrow can only veer off so far before it hits the target, but at 50 it has 30 more yds. to exaggerate even the smallest misque. Another thing to think about is make sure your sight and pins are tight and not moving around on you. Just tryin' to give you some things to think about, Good Luck.