I just received and mounted the ARMS M21/14 Mount Foundation (#18), ARMS Dovetail/Stanag Throw Lever Mount (#19A) and the ARMS STANAG Rings (30MM) (#21). I ordered and received all items from Arizona Gun Runners. This system was very easy to apply and no special tools required. I am planning to put a Leupold VARI-X-III 3.5x10x40 Long Range M3 with bullet drop compensator. Does anyone have any Pro's or Con's about this sytem or any tricks that I should be aware of?