I doubt that you will ever get it down to 2-3lbs
The design is not set up for that. The manufacturers had trouble getting them down under 8lbs in some cases, 10lbs. They changed the hammers, hammer springs and sears and got them down somewhat. If you have a later model, you will see the sear is polished at the contact point, this helped somewhat. It just isn't a target piece. With handloads I can hold the ten ring on an SR-1 at 100yds with my NPM (which was one of the better makers). The trigger is a lot like a stock M16, not crisp, and too heavy.