The lead sled doesnt clamp to your rifle , the rifle just sits in it, the rifle still recoils as if you were shouldering it just the rest takes the recoil instead of your shoulder. you have to see it to understand what im talking about. But after zeroeing my rifles with the lead sled then to make sure it was a true zero I shot again with the rifle just resting on a sand bag all 3 shots had the same point of impact as with the lead sled.