The MOA/BDC reticle is not going to work well with a barrel that short. It's calibrated more along the lines of 18" barrel velocities. If you are running with the mil reticle, I think it'd be fine, you would just need to memorize your holdovers. Whether you're going to shoot far enough you need to memorize them is up to you, I guess.Most of my ARs are short, and I am wondering if it is a waste to put that much scope on a 12.5. I could put it on a Scar 16, also short but it shoots bugholes whenever I actually shoot it for accuracy, or on an MDR -- 16 inch barrel, shoots well, but I don't use it a ton. All set for hunting rifles. Sigh. What do you think?