Had short-stroke problems with my Bushmaster Shorty AK, even after 700 rounds. Followed advice in the "Troubleshooting" section and tried Tetra Grease, but that gummed everything up BAD after 40 rounds.
Just got that upper and an M4A3 back from Kurt and decided that if I don't get it to work it's gone. I mated a brand new Bushmaster lower with the 14.5 HBAR upper (the previously Shorty AK), and the previously Shorty AK lower with the brand new M4 upper.
I stayed with CLP, and clipped one turn of the buffer springs on both lowers. 350 rounds went through the M4 with about 5 short-strokes (all within the first 100), and 300 went through the 14.5 HBAR with about the same malfunction count / pattern as the M4, so now I'm happy.
They are both enroute to my location here overseas, and as of right now there's no chance for me to shoot them. I do think though that our unit is going to start running M16 ranges, and I've volunteered to go through range certification. This means that if we do run the range then I'll be able to shoot my AR's on Uncle Sam [:p].
If not, then it will be mid-2003 before I can shoot them, which is when I get back to the states.
Chris