I've had a stripped lower sitting on the shelf since last year. Finally got around to getting an LPK and getting to work on the build on Monday - assembled it Monday night when I got home from work. Dumped my bag of parts onto a cookie sheet in my work room and in about half an hour (because I dropped the bolt release spring, the hammer retaining pin, and a detent on the ground at different times) I had an assembled lower, sans receiver extension/stock/buffer assembly. I slapped the upper from a complete rifle on it to test trigger function and pull. Trigger felt fine, but there was a hitch in the giddyup - the hammer was following the bolt, except when I let pressure off the trigger. Pulled the upper off, and compared the build-a-bear lower to the factory Bushmaster lower - I *thought* the disconnector was out of spec, as it wasn't engaging the the hammer, and didn't appear to be protruding as far forward as the factory disconnector. I was ready to take the lower by Oregon Arms where I bought everything, and see about swapping disconnectors on Tuesday. But I woke up Tuesday morning and something was bugging me. I pulled up a schematic of the trigger assembly before I got dressed for work, took the trigger apart, and realized I had forgotted one little, but majorly important part - the disconnector spring! Installed the spring, re-test trigger, everything works A-OK and no more "following" of the hammer. One pull one click. Reset feels just like my Bushy now. I am a bit disappointed in the selector though - it isn't as crisp and has more "wiggle room" than my factory gun. With the hammer down, I can move the selector about 10 degrees or so toward "safe" on my franken-lower, the factory gun barely wiggles. I'm wondering if I should replace that spring, the detent, or the selector itself, or if that wiggle room is within tolerances? When on "safe" the pressure to deactivate seems normal, it's just when on fire that there's a bit of slop. I'm at least a lot closer to having a functional rifle than I was a week ago. Got to figure out which direction to take the build. I was originally going to build an AR-pistol with a Sig brace, but now not so much. Not sure if I want to fork over $200 and 9 months of waiting to SBR it either, probably will wind up with a vanilla carbine and be done with it. Or maybe I'll make an A2 style rifle. Too many decisions.