I must admit, I glazed over the fact that it was a 7.62... That being the case, I think 16" is more appropriate. I'm of the idea that I will go as short as I can and always have the length of a suppressor in consideration. I have a 1.5-8x on my AR setup (5.56)now and ran it in a match the other weekend. It was a DM match and I thought I would have an ideal setup. Well, the match turned out to be more of a short range PRS match with tons of time and small targets and I found myself wanted a lot more magnification. By no means am I getting rid of that optic, it will go on deployment with me from here on but I do intend on getting something with more mag to try and hang better at these matches. A rifle like the one you're considering, I would have at least 12x and a reticle that let's you do accurate holds. Keep it short and fast.