Dardick tround
（重定向自Dardick）
The Dardick tround, or simply tround (triangular round), is a unique firearms cartridge developed by inventor David Dardick for use in his open-chamber firearms. Named for its convex triangular shape, the tround allowed the firearm's chamber to be open on one side, removing the requirement for reciprocating motion when chambering and ejecting a cartridge.