how about a toothpick and some scotch tape? ...not the best but definately quick and easy for a bare shaft shooting session....guess where to put it first then move it untill your close enuff that your not going to miss the target, then just put the pin in the same spot on the target every time and shoot your groups. thats how ive done it anyway with a recurve, might be trickier with a longbow since their isnt really much of a sight window and most guys will cant their longbows more than a recurve witha center/past center cut shelf.....