If it's a new S&W I'm not surprized you found the trigger a bit heavy, it seems that most are now shipping with triggers in the 11 to 12 lbs. range. Personally, I think they are doing this as an additional element of safety, it's difficult to have a negligant discharge with a trigger this heavy.
Good news is that it can be tuned to a much lighter weight, however it's best to use a gunsmith who is well aquainted with the newer Smith The frame mounted firing pins on the new guns provide an additional area of tuning that can effect both reliability and accuracy.
First, I'll tell you that you should start by running at least 500 to 1000 rounds through the gun in double action. On the MIM lockword this will do a lot for smooting the DA sear surfaces. In addition it will show any rub marks on a hammer or trigger that may require a touch of fitting. BTW, the hammer will rub the internal lock a bit and you can safely ignore that rub if it's minor.
I've been experimenting with a model 620 and now have an 8 lbs. DA trigger that is 100% reliable for ignition with Speer Lawman and is also very very accurate. The recipe is actually pretty simple, a 14 lbs. rebound spring has been installed along with an extended travel firing pin from Cylinder & Slide. As for the mainspring I've reduced the tension by installing a 0.020 inch thick handmade shim under the head of the strain screw.
Now for the bad news, if you want to take on doing this yourself you will need some items that I consider essential. First is the Kuhnhausen manual for the S&W revolver, there is a trick to just removing the sideplate and it's well illustrated in the manual, along with many other tips for smooting the trigger. Second you'll need a specific tool to install the spring for the rebound slide, without that tool doing this approaches impossible. Third is a good trigger pull gage, I prefer the Lyman digital because for 60 bucks you get a very good gage that is easy to use. You'll also want a set of fitted hollow ground gunsmithing screwdrivers so you don't bugger up the screws. Then you'll want to purchase a few small parts, personally I would recomend a 14 lbs. rebound spring and that extended travel firing pin from Cylinder and Slide. BTW, you do NOT want to use this firing pin until the DA pull has been reduced to at least 9 lbs.. With the factory mainspring setting this firing pin has the potential to pierce a primer. Something that you absolutely do NOT want to happen in a gun with a frame mounted firing pin because the only way I can concieve of to get it out of that primer is by going in from the barrel. Finally, I would suggest that you purchase one or two spare strain screws. I made those shims I mentioned using a Dremel equipped with diamond burrs and it's a bit tedious. With some spare strain screws on hand you can shorten the strain screws in alternating steps until you get the DA trigger down to 8 lbs. by trial and error.
Note, every single item mentioned is in the Brownell's catalog so if it's in stock you'll only have to pay one shipping charge. Unfortunately it seems to be a bit rare for find everything you need in stock at the same time, currently the S&W manual seems to be out of stock. When I ordered my parts kits I had to get the firing pins from Cylinder & Slide.
Finally, when I first took the 620 down to 8 lbs. I found that ignition was completely reliable using Speer Lawman as a testbed ammo. However I also found that the accuracy had degraded and saw a distinct tendancy for vertical stringing in my groups. Installing the extended travel firing pin cut the group sizes in half. Just one small change and my groups at 100 feet went from 3.5-4 inches to under 2 inches. Quite simply, if you want to push the limits on the DA trigger pull you have to pay attention to all the details, just lightening the mainspring won't cut it. I'll also warn you that the wide target hammers require a bit more power in the mainspring than the lighter service hammers, target hammers are heavier and it takes more power to get them up to speed.
