I bought one of the Arken EPL-4, 4-16 x 44 scopes and have tried mounting it on two different rifles in 2 different sets of rings......Warne Maxima's and Burris Extremes with the same results. When torqued to a little past hand tight, the parallax knob is stiff and catches when i turn it. When torqued to recommended specs of 18 in/lbs, the parallax won't turn at all. I have tried mounting the rings as far away from the center and closer to the center with same results. Any suggestions?