The term single stack refers to a type of handgun magazine and, in some cases, the type of firearm that can accept a single stack magazine. Typically, micro- and sub-compact handguns have a single stack design since the grip is too narrow to accept a wider, “double stack” magazine. Also, traditional 1911-design handguns are dubbed “single stack” firearms. The downside of single-stack firearms includes a lower round count (typically fewer than 10 rounds). SIG SAUER solved this problem with its revolutionary P365, which is a micro-compact handgun that features a 10-round double-stack magazine.