I went IN in '96., but since we were stationed away from the front (air defense) they never got around to issuing us the M4.
But yeah, I do miss the M16...after firing other weapons, nothing just "feels" the same.
By the time I got out, I had the M16 mastered, and could nail my way through the range almost without effort.
Last range I went to, I had a distracting coach...and had just nailed 20/20 in the foxhole position. My weapon was unloaded and next to me when I heard the tower call to lock and load, and commence firing for the prone. I had to jump out, roll over (grabbing my weapon and magazine in the roll), slam it home, lock/load then aim. I ended up missing the first target with no shots fired, second target I popped two quick rounds at (missed) then got the rest.
Ended up with a 38, but I was still proud. IMO, more accurately assessed my performance under pressure.