SporaS, how often do you use the pump, are your guns leaking?
I might use it once every two or three months.
I'm starting to think my 150 is leaking, I've tried pumping air and it doesn't seem to get any more pressure and the bottom aluminum part of the pump (closest to the oring and threads) gets really hot after 10-15 pumps. When I say hot, it feels like when tanks have just been filled up.
BTW.... When the guns are at the LDS, I have them make sure there at 400psi with the manometer.