The longer barrel will not necessarily get you any accuracy. Normally it is believed that short barrels can be more accurate because they are more rigid. Since you are looking at a 22LR I am inclined to be of the opinion that the extra 5" of barrel will not be worth a whole lot in velocity, so if you like the knob and threaded barrel of the FV-SR I'd say go for it and enjoy.

You could look at the Mark II TR. It has a slightly longer barrel than the FV and has the knob you like and a fluted heavy barrel. Looks to be a few extra bucks though.