I haven't blown the pack yet. I have taken the cartridge out and pull the cord activating the burst pin and such. The pull is very short. It snaps into place. The key thing I take from it is to make sure the bladder hose is stashed away from the handle. Which by the design of the zipper it was pretty easy to do. I'll probably get to blow it this week. Looks like I need to spend some time working on my car and there isn't much snow in the forecast anyway. Should leave me with time to mess with the pack and get the cartridge refilled.