I have four air bottles two of the smaller type and two of the bigger type.I fill them with a stirrup pump and no problems to begin.For some reason the smaller bottles fill to 3000psi no bother.The larger ones get to roughly 2200 psi then you open the bleed valve on the stirrup pump and it drops all the air out of the bottle to roughly 1000psi. Any one have a idea what's going on ?