It was weird how it happened. The way my military bench is setup it has options of racking the barbell either behind you or in front. I don't like using the back rack because its awkward to get it lifted off w/ot a spotter because its too far back. I had it on the back rack warming up with 135lbs and when I went to re rack I went to put it on the back racks but I changed my mind and was going to rack it to the foreward hooks and BOOM out popped my shoulder. I managed to get the bar straight over my head again and thank god it popped back in. Freaked the hell out of me. Hopefully you guys can understand what I just said, because it isn't even that clear to me and I wrote it.