Tgigger pull on S&W 29-2

[bidemhi]

I recently acquired an S&W 29-2 in beautiful cosmetic condition but I'm concerned about the light trigger pull. I don't have a trigger gauge to measure it, but it is very light. The hammer will not fall if I try to jar it, and I think it is perfectly safe, but I would like it a little heavier. The mainspring screw is screwed all the in and there is no adjustment there. Would a new mainspring help or will I have to fit a new hammer and trigger assembly? I have no way of knowing, but I suspect that this gun has had some action work done at some point in time. Thanks, Bidemhi