Here's one option. Very compact and lightweight (I think it weighs less than 1 once). I currently have this JPoint mounted on a FA83 .475 Linebaugh using the FA mounting system. My everyday load is a 400gr bullet at a chronographed 1,150 fps. Have shot close to a 1,000 rounds of this load with no problem.
Here is a thread at Greybeard Outdoors discussing red dot sights on FA revolvers http://www.go2gbo.com/forums/index.php/topic,202284.0.html. Look around in the Freedom Arms section and Handgun Hunting and Handgun General Discussion categories for more discussion of Red Dots and Scopes.
Hope some of this helps.
Paul