I just came inside after shooting a couple hundred balls in the backyard, testing my rig. I took the barrel and hopper off my gun (BT4 ERC) to clean. Sat my waist pack down, which holds my 68/4500, remote line still attached, knob screwed out and no pressure in the line. I turned around and started cleaning my barrel.
*LOUD POP* ... loud enough to make my ears hurt just a little. Much louder than a marker shooting.
My first thought was "great, my tank just blew up". I check it and there's no signs of cracks or anything on the outside. Pressure guage still about 1000 psi, right where it was when i set it down. I removed the remote line, no visual problems.
I checked my other HPA tank that I hadn't used. Gauge psi right where I left it. I have a milk crate full of older CO2 tanks nearby, nothing looks any different.