i havent had any problems with any of my AA systems having drop off. take it apart and clean it/ replace any o-rings that may be damaged. what gun are you using and what kind of secondary reg are you using? it might be the secondary reg. sometimes apoc dont like going to low, so try upping you pressure output to 600 or so, see if that helps, that may also help a bad secndary reg. some apocs dont have the correct spring pack to go below 400 psi. you can also send it to AA and they will check it out. tell them what output you are running and they might redo the spring pack for you. and you havent replaced the reg seat with a mag seat have you? that might cause drop off also.