I've had a Fast Fire II on the front action ring of a Winchester Model 70 and it sat way too high to get a good cheek weld. I would recommend, if you want to use a reflex type sight, having a dovetail cut into the barrel ahead of the receiver ring and then mounting the scope onto that in order to get it as low as possible. Also, I doubt the FFII will survive the recoil of your rifle. The sample I had did not inspire confidence in terms of ruggedness, unlike the Trijicon reflex or the Docter Optic, of which the FFII is a copy.
Here's a pic of the FFII on a Model 70: