Sir,

First of all, let me welcome you to the forum; and I'm always glad to hear from new shooters seeking some assistance.

I'm a bit surprised that no one has yet asked you what it is that you're looking to accomplish with this gun. The answer to that question will, to a large degree, answer your question(but not completely). Let me try to explain myself.

There are two major, and very different, uses for a revolver: 1)defensive; and 2)target, or 'bullseye'(Hunting is a 3rd major use, but I'm including it under 'target', since the process of becoming more proficient is very similar for both.). Both require range practice in order to become more proficient, but that practice is much different for defensive shooting.

You posted later in the discussion that you ultimately want a J-frame, which seems to indicate to me that you want a gun for defensive use. Am I correct? If so, then shorter barrels are the order of the day. There's more than one reason for this, but let me summarize it by saying that shorter barrels are more easily maneuvered and retained in the very short-range, rapidly-moving situations a typical defensive encounter entails(And no, I've never experienced such a situation and pray that I never will -but one need not have such experience to know the advantage of a shorter barrel under those circumstances.). If you plan to carry your defensive gun, especially concealed, the advisability of a shorter barrel becomes even more obvious.

Having said all that, it doesn't appear to me that there is really enough difference, for defensive use, between the 3 and the 4 inch guns to matter all that much. I have 4" 686s to defend my home, since a home defensive encounter is more likely to involve a longer-range shot and more warning that something is amiss; and a 2-1/4" Ruger to carry outside the home.

Either of the options you're considering may of course be used for target shooting as well, if one so chooses. But, as has been mentioned already, longer barrels such as the 6" provide a longer sight radius to help make those groups smaller, which of course is the goal of target shooting. All my target guns have either 6 or 8-3/8" barrels.

Well, I'm up way too late and have to wrap it up for now. Others are more expert than I -just thought I'd throw in the above issue if it might help you clarify in your own mind what you want to accomplish.

Best wishes in your choice, and let us know how things go for you,
Andy