I have a number of Leupold Compact (now called Ultralight) 3-9's on L461/A-I Sakos. They are a beautiful match in my opinion. I don't think that Leupold makes a 4-12X in this model, but they do make a 2-7X, which is also nice. Compared to the full-sized 2.5-8 VX-3 or the 2-7X VX-I/II, the "Compact" models have a little more restricted eye placement and field of view, but that is an unavoidable optical compromise in order to achieve thier small size. Nonetheless, they are better in these features than many other manufacturers' full-sized scopes and I've never found a problem using them. Burris makes a 4-12 compact scope, but two friends who have briefly owned these scopes have told me that the eye placement is so critical as to make it impractical as an optical gunsight. With the 3-9 Compact/Ultralight, use the Leupold "low" ringmount on your A-I and never look back.