Your stock trigger might wear in and smooth up, but it won't get significantly lighter unless you reduce the springs.
If you're OK with set screws, the
JP trigger is nice and allows pretravel and overtravel adjustments. I have one, along with their
light hammer, and even with their reduced-power springs have never had it not fire any .223/5.56 ammo, including mil ammo like XM193 or South African M193 surplus. I believe I've read of people having issues with the light springs and a normal weight hammer though. For a little more insurance go with their Service Rifle Spring kit, which should have a stronger hammer spring. The JP trigger works with the regular hammer and you can cut the tail off the back of your stock one to reduce the weight if you don't want to pay for theirs.
The Accuracy Speaks trigger is recommended here by quite a few people as an improvement over the stock trigger without any adjustment screws.
Or you could check out the
15-minute trigger job for instructions on bending the springs. You could try bending the hammer spring legs just a little to drop the weight, but less than going to a full reduced-power set.