Okay, but for the shooting you're talking about, you don't need the Tactical model. The Tactical model has the large target-style adjustable turrets, which is nice when you're going to be sitting at a bench with all the time in the world to dial in a distance and windage estimate. On a rifle such as an AR, you'd probably neve adjust the optic in the field (and honestly, doing so would be a pretty bad idea), so you'd be better off with the standard model. You zero once and leave it alone. Plus, you won't have those big tall turrets banging on stuff.
But, I'd seriously look into an AimPoint or EOtech first. Even a 20" AR shooting M193 is limited to about 200m of range where the bullet fragments, which is where it causes major damage. Beyond that, no fragmentation, and severely reduced lethality. Both the AimPoint and the EOtech easily allow you to hit man-sized targets out to 200m despite no magnification, and they are super-quick at getting you on target. That *won't* be the case with the Leupold, which even at 3X, will take you a while to get on target.
If you do go with a conventional scope, I recommend the Armalite one-piece mount. IMO, it's the best mount for installing a conventional scope on an AR.
-Troy