yes i am certain. i filled it on sunday hadnt used it at all. fired about 10 shots through my marker. it was on 1500 psi before i took it out while it was working. i unscrewed it, then bout 20 mins later i screwed it on again, it fired about one complete shot and then pressure dropped on my gat and no shots fired. then i unscrewed the tank and was able to push the pin in at the top and no air came out.