I've had a SWFA fixed 20X for about a year now, mostly on my .22 indoor rifle. The scope has been on a .50 BMG for about 10 rounds with no ill effects. I like the scope overall, especially for the price. My tracking test on the turrets shows that it is off however. I only need to dial 9.6 mils to get 10 mils of impact adjustment. I'm not going to send the scope back for a fix, it resides mostly on my .22 anyway.