The 686 frame is strong and would serve your intended purpose. There is a reason why S&W has sold that many over the years. I have had a few 686 and 686+ over the years but the 586 L-Comp would probably be my suggestion. My L-Comp has displaced my 686+ in my collection and DC rotation. I love the idea of that 7th round "for free".
I know I am opening myself up for tons of flak, but the GP100 is also a tank of a .357 and is as strong (here comes the rotten tomatoes being thrown my way) or potentially slightly stronger. However, I think you'd be in that 200k+ realm before any difference of the 2 could ever show up if it ever did. Just a viable alternative but the 686+ / 586 L-Comp would of course be my first choice.