My shooting partner has one on a .223 though I can't remember the power, I think it is 5-20 maybe? Either way, he has been very pleased with the scope. I have personally watched him shoot from 100 out to 600 and back with no problems. I have looked through the scope on numerous occasions and the glass appeared to be good quality. The only place I know it has come up short thus far was in low light where it just didn't have the same capacity as the Leupold and NF scopes on other rifles sitting next to him.