I live about 5 minutes from the guy who invented these! I will say they are pretty dang neat and DO work but it takes some shooting to get used to looking threw them, I guess what I am trying to say is that its not natural feeling to me.
The only gun I have personally seen that it didnt work on was a shotgun with turkey loads, it would sling your phone out everytime it was shot but he has come up with a method to eliminate that !
He has shot them on every rifle he could get his hands on (if he didnt own it) from a 22 cal to a 50 cal and NO blemishes what so ever except the turkey loads.
He even mounted one on his Hoyt and in his shop within a matter of 10-12 shots he had quarter size groups at 30 yds !! Granted he had a full size rifle scope mounted on his riser and it didnt look all that great (kinda bulky) but I kid you not it WORKED !
He is a down to earth guy who trying to make worthwhile of long hours and countless dollars spent on fullfilling his dream, its costing him alot but I applaud his determination and he has come along way.
I AM NOT TRYING TO SELL HIS PRODUCT BY NO MEANS, just wanted to state what I know about the product and the guy who invented it, he is like the rest of us, hard worker who loves the outdoors.