Most gun vices are not attached to the shooting bench but they can still have an effect on point of impact as can anything that is solidly attached to a rifle .Even bipods can effect the point of impact with some rifles.The only way to know for sure is to check point of impact with and without these devices.I give this warning because I have seen far too many people use these gun vices to sight in their guns without bothering to check to see if their setup does effect point of impact.Sometimes it has no noticeable effect but sometimes it can cause point of impact differences that could result in misplaced shots while hunting.