NHSport, my brother, I feel ya! I am fighting the same battle myself at the moment.
My DPMS will shoot 3/8" groups at 25 benched but the trigger is holding me back in offhand. I do a lot of 25 yard offhand shooting with a number of different .22 rifles and invariably shoot the DPMS the worst.
I recently got the new Rhineland Arms R22, which uses AR FCG parts. This had by far the worst AR trigger I've ever pulled, heavy and extremely gritty, and I've shot hundreds of them. The problem was a very roughly machined sear surface on the hammer. I carefully stoned both sear surfaces (hammer and trigger) very smooth and lubed them and the trigger is now about 5-6 pounds, with a typical AR amount of creep, but it's very smooth. It's now sort of like a Glock trigger with the 5 pound spring in it. I can now shoot the R22 offhand about as well as I shoot most of my .22 rifles.
Now this is important: The R22 uses a special hammer spring, which only has the right leg. It takes noticeably less effort to cock that hammer than any AR I've ever seen.
Just today I stripped out my DPMS .22 and stoned the sear surfaces to see if I could get its trigger as nice as the R22's is now. Its hammer and trigger surfaces were already pretty smooth, so my polishing efforts didn't help nearly as much. It's smooth now, but the full-strength hammer spring is keeping the pull weight up somewhere around I'd guess 8 pounds.
My next step, I guess, is to see if I can find a reduced power hammer spring for the DPMS and see if it will operate reliably. Reliability is excellent with the R22 but it uses a Ruger 10/22 bolt and firing pin.
The adventure continues....