I run the Daytona m249 with a EI SKD molle chest rig and a camelbak. I can squeeze 2 HPA or CO2 tanks in there and when I need to drop the gun, I could drop the tanks as well. Looking to build a double regulator system so that the 2nd tank is already connected. My main rig has a molle tank pouch on the back panel for when I run the Daytona AK or my eventual MP5/M4 Polarstar builds. I recently received me adapters to run HPA to my m500 for CQB.