I’ve been using UM Tactical accessories for years, primarily their handgun optic mount for semi-automatic pistols. Now they’ve made a leap into the hot category for 2017 – pistol caliber carbines. The UM Tactical SS9 is an integrally suppressed, 12-inch barrel carbine. It accepts any Glock 9mm magazine, so you can use the short ones for discretion or the big 33-rounders for capacity. It operates with a left-side, non-reciprocating charging bolt which locks back when the magazine runs dry.
It’ll require two tax stamps (for now) due to the suppressor AND short 12-inch overall barrel length. Very cool.