I have one on my 135 Carnivore and my 125 .25 now that they are both sighted in and I've figured out how to use them they a a very good alternative to open sights because of the quick target acquisition. They have stood up to recoil not loosening at all. They are now a permanent fixture on these rifles. Make sure you loctite the screws. Once they are sighted you probably won't ever have to do it again. They should make this sight to fit a dovetail. I've suggested it to them multiple times. As it is it will only fit certain air rifles.
I really like them and would recommend them to anyone that likes to shoot without optics.