If you can - wait for Black Friday. They typically have a couple hundred off of the 3-15 line-up.
I've got several of their fixed and variable scopes on bolt guns, and tend to use lighter scopes on my ARs. Mainly because of the types of shooting I do with each, the SWFA don't get mounted on the ARs for the weight, and I don't usually need the high end of the magnification range.
Having said that, I wouldn't have any reservations about mounting on a AR. I'm working on a 6.5 Creed build that may get a SWFA 10 power on it, haven't decided.
I was able to take a 3-15 FFP out to 1200 yards last month, it was spot-on for dialing ranges and for quick reticle hold-overs. In three days of dialing, it did not miss a beat.
I would recommend getting a zero stop for the SWFA knobs, it will help if you are reaching out in distance.
Last edited by AH64guy; 08/17/17.