Most of you guys are more charitable than I am. I'm frigging sick of 3-4lb triggers. I'm swapping all my non HyperFire ones to the newer Trigger Tech Diamond. No reason to shoot over a 1.5lb trigger ever, IMO. And a Mil-Spec 7lb POS.??...don't even get me started...
The 4-1/2 lb Service Rifle minimum is a holdover from the M-1/M14 days where going lower than that introduced a very real possibility of doubling or worse.
The first AR Match triggers were based on the M14 design (ie Milazzo-Krieger II and the copycats that followed), thus they had the same tendencies and limitations. I think more engineering has gone into AR triggers since then to produce safe lighter triggers. I've not followed all the advances, but I'm not sure I'd still be comfortable with a single stage AR Trigger lighter than 4lbs. That's asking a lot of a little lip of metal.
