If you can make 40 yards on the target range, thats awesome, but leave it there. Turkey's don't hold still for nothing. It really doesn't matter how good a shot you are, you should probably limit yourself to no more than 25 yards with turkeys and a bow. Their eyesight is just too good. I don't think its "string jump" I think that they can see the arrow coming, or at least see something that ain't right. And keep in mind that 6 inches at 60 yards is about 4 inches at 40, and thats PLENTY to screw up a turkey. Being off any more than two inches is a loss.

Not trying to give you a hard go here, but just keep in mind that if you don't shoot, or more appropriately if you don't cripple it up, then it will be there tomorrow. Admittingly, you won't ever take one if you don't shoot, but a little discresion goes a long way.