Basically as the title states. I have an Apocalypse tank regulator that I bought used. It is/was in fair shape. I put it on a 92/45 Crossfire tank and it worked fine for the first three fills. Those fills were to 2800psi on a cascade setup just for test firing and messing around. Then I took it to the field and filled it to 4000psi (off a compressor) and when I turned it on it blew my macro fitting & hose off the reg. I bled the tank by cracking the on/off, replaced my fitting and hose, and refilled the tank. I turned the pressure adjuster all the way down till it was almost falling off so I was sure the reg wasn't set too high, but the second I turned the reg on it did the same thing again and blew my fitting & line off slicing my hand.

What could cause it to feed full tank pressure when the adjuster was backed off all the way? Do Apocalypse's have an overpressure burst disk on the output side? Should I get a braided steel line and run it as is (it's on a Classic RT)?