Abstract: A rupture mechanism is integrated into a plastic casing used for low velocity projectile rounds. The casing incorporates a cylindrical wall having a top mouth end that fixedly receives a projectile to be launched, and a bottom base head at the bottom end. A low-pressure chamber is formed by a first interior space between the cylindrical wall and the bottom base head. A high-pressure chamber formed on the bottom base head extends into the first interior space. The high-pressure chamber is formed with a second interior space to receive an ammunition cartridge. A top portion of the high-pressure chamber has an integrated burst area wall with a thickness selectively formed based on a type of projectile fixed at the top mouth end. Detonation of propellant gas from the cartridge builds up pressure to rupture the integrated burst area wall with a delay time in rupturing the integrated burst area wall based on the thickness of the integrated burst area wall.

Abstract: A collapsible serving tray that is stiff and flat when open and reduced in size and compact when folded. The tray is designed to be folded up into a compact size that is about one-quarter of the fully deployed size of the tray. One embodiment of the tray includes a perimeter edge that is ninety degrees to the flat serving surface when the tray is fully deployed.