I'm getting old and my shoulders are screaming for relief every time I come back from the range. I don't shoot my 300 Win mag bolt gun much, but at 7 lbs + weight of scope, it constantly reminds me of how I am going to feel driving home. I also punish myself with an M1A and have fun with ARs. I was curious if anyone has seen group size improvement using the led sled plus to work up loads. I;m told that it eliminates the human error???? Some have pointed out that ARs and M1As will not fit due to mag length and hand grips. Is there a way around this? Are there any disatisfied shooters? Thx!!!