I shoot with a guy that just had red dots mounted on several of his revolvers, even a S&W 43c which is a snub nosed DAO 22. We shot a match this weekend (pocket gun concealed carry match) and he shot 2 entries, one with a red dot, the other just like it but with irons. Irons, he got 21 A zone hits, red dot he got 33 A zone hits if I'm remembering correctly. It certainly makes a difference to a guy that just can't see the front sight.
I have an RMR with the 3.5 MOA dot that I like really well and I have a JPoint with an 8 MOA dot on my steel challenge gun. Bigger dot isn't really any faster that I can tell but the RMR has a bright red dot where the JPoint is more of an orange dot. My 629 Mountain gun is drilled and tapped but as long as I can see the Dawson FO front sight, I'll stay with it but it has crossed my mind.
I've seen women who have never shot a handgun go from barely hitting the paper with open sights go to decent 2" groups with a red dot on a .22.
Her BF came down to my lane and asked if I could help his GF.
I went down and helped her a little with trigger control and basic hold and importance of the front sight.
She got most on the paper after that and on a hunch I went back to my bench and got my Ruger Mark II with a first generation Holosight on it and she shot so much better she was very excited.
She asked him why he didn't have a gun like that. It's hard to make women happy.
