I have both, the 317 is very light aluminum alloy (cyl is alloy too) about 10.5 oz. I like to throw it in my pocket when going for a walk. I was lucky to find one without the lock.
The M63 goes with me every time I go to the range, it's stainless steel and weighs about 24 oz. This one is on the "never sell" list.
Both are 8 shot.