A 'bud' is a disc of black paper pinned over the bull to give a better aiming point. They are almost always used in chunk, plank, and table shoots. The idea is to place your bud so that your shots go through the centre of the bull, no matter how your rifle is sighted. In fact, shooters deliberately sight their rifles to hit in another place other than their aiming point, so that their aiming point does not deteriorate during the match. That is not my concern in the case of this ALR postal match...just to give me a sight picture that I can see at 50 meters.