re: open sights
I have an FNAR, and have open sights on it. There's a couple ways to go.
1. (my choice)--Magpul MBUS sights mounted on the factory picatinny rail. They are only about 6" apart, but that's as good a sight radius as you get on a 6" revolver. For what I wanted, which was emergency back up out to 100 yards max, this works OK. I can hit a piece of notebook paper at 100 yards without a problem if I do my part. Probably would be better if I had more experience with that type of sight and practiced more. If you then mount a scope on top, like I did for short range hunting and/or 3-gun type matches, you have to use ultra high rings and a low power scope, but it works fine for me. I got the Warne quick-detach ultra highs and a Weaver 1-3 scope. I can use the scope for anything from 0-300 yards, and if I get a wild urge to shoot open sights, I can just yank the scope off and do it. And when I put the scope back on, it doesn't come back *close* to the same point of aim, it comes back to *exactly* the same point of aim.
2. Have a gunsmith mount a sight somewhere on the end of the barrel. Expensive. Will it affect accuracy? Will it match up with a rear sight on the back of the picatinny rail, or will the gunsmith have to drill and tap for the rear sight too? Never asked those questions myself. Just went with #1.
Does this help any?