Trigger pull can be decreased some by using either an 11, 12 or 13 pound rebound spring and an 8 pound mainspring. For the latter, you need to fire a fair number of you defense loads to make sure there are no ignition problems.
You can also reduce trigger pull by stoning the rebound slide surface, the interior of the frame where the slide engages, and deburring (if necessary) end of the mainspring strut that engages the hammer.
** If you do this, and you are the first purchaser, you will VOID your factory warranty. So you need to know what you are doing. ***
The drawback to a lighter rebound slide spring is a weak reset. To help with this, you can polish the bottom corner face of the hand that drags across the extractor star ratchet as the hand moves downward when the trigger returns. You can also polish the corners of the ratchet where the hand *returns.* DO NOT polish the upper part of the ratchet where the hand engages.
See here:
http://smith-wessonforum.com/s-w-smithing/409454-question-about-j-frame-cylinder-stars.html
You can also polish the surface of the trigger and the surface of the cylinder stop that engages the trigger. Be very careful there, too.
On one 642 I've managed to get the trigger pull down to about 9.5 pounds or so, and it has no ignition problems and reset is brisk.
But I did that mainly for tinkering. You will never get these guns down to a 7 pound pull, for example. I don't mind the stock triggers on these, and I mainly do this on my guns just to tinker. I'm restless that way.
Or you can pay about 70 bucks and have a gunsmith do it, too, and at least have the confidence that your gun will not be accidentally ruined by the Bubba looking you in the mirror.
