I was somewhat pleased with my 7-30x50 Leatherwood uni-dial until today. It would probably be fine for 7mm mag or lower, but my .338 rum sheared the elevation knob off... I got about 100 rounds through it before it failed. Not impressed. The set screws holding the unit in place only had about 2 or 3 threads of penetration apparently and stripped out... Customer service is good though.