I'm going to have to respectfully disagree with the above two posts. I've had a Shepherd atop my SR-25 for about four years and have found it dead reliable and perfectly suited to a semi-auto weapon. If you have to rapidly engage multiple targets at multiple distances nothing else, with the possible exception of the re-reticled Schmidt & Benders, come close.
The horizontal and verticle minute scales in the Shepherd completely outclass any silly mil-dots for range finding. Not only are they easier to read but, a normal human being can easily do the required math in his head.
It is NOT an X-ring scope. The cross hairs are too thick for that. It is meant to put a hole somewhere in the A-Zone RIGHT NOW.
Where most guys run into problems with the Shepherd is not reading the instructions. Once you come to grip with the fact that there are two reticles in two different focal planes, the scope is very easy to get along with.
Caution: Make sure that the flight path of the bullet leaving YOUR rifle in fact duplicates the BDC reticle of the Shepherd. I strongly recommend the Pejsa ballistic program for this determination. In my case, a 175 gr. Sierra HPBT parting company with the muzzle at 2,600 fps will track that reticle like it was wire-guided.
Luck,
SD