Adjustable trigger set screw - it made the LPK go from typically horrible milspec to hunting grade in on adjustment session. Now it has almost no creep, and because it took out 80% of the travel, most of the grit is gone, too. It's what really does the job, look around at all the precision triggers, most have that screw.
A3 flattop - the rail mount allows an easy cholce of mounting optics gunsmith free. Mounting a red dot becomes a no brainer, less than one minute, vs the 20 minutes of scope bases, rings, scope, and rework when it needs tweaking to get right. For that amount of time, I could be pulling into the range parking lot, with another optic to test on the spot, no little screws or fuss to mount up between magazines, either. In the field, I could install another and still be hunting accurate in the same time it took to screw up the first one. Another day of hunting vacation in the field vs. a ruined trip. A BUOS is better than BUIS, at least if you did bother to get good optics to begin with.
Red dot optic - been shooting one since I bought a 1GEN Aimpoint in the '70s, which I still have. They work better than scopes for me, a less restricted view in the window, no hunting for the target, both eyes open, put the dot on target and squeeze. They work twice as fast for me, leaving more time on target for better precision. For some reason I can't get them to pose like they do in the videos. Maybe they're wild compared to the hand fed ranch deer those guys pay to hunt.
