No. really no problems. I want to make my own M2-2, m2_3, etc. sounds. I make the m2 sound which is just a single .50cal. The M2_2 I think would be 2 .50cals. IE an side gunner on a b17 would use 1 m2 file, assuming that is the only gun he is firing.
Where as a tail gunner would use an M2_2 file if that were the only gun he were firing. I have the exact same file as m2 and m2_2 but it seems AH takes the M2 file and runs it thru some audio effects to simulate the m2_2 situation. I can hear rounds per minute increase, which is ok, but there is some cheezy echo reverb tremelo stuff in there also, which i dont like and dont have the time to airbrush it out. But it could be the stereo effect, although I have had no trubble with my stereo engine sounds.