I've been kicking thus idea around in my head for quite some time now. It's a 30 caliber (308 to be exact.) The barrel on it now is a 7.62 blank so it's not going to stay on it, hence why it is shorter than the tank. My goal is to make affordable yet powerful PCP's for the market and this design makes it quick and easy to manufacture them. I still have a ways to go but it won't be much longer before I'm test firing it.