Believe it or not, there is one gun very notable for having been taken by the United States Air Force to other planets. That said, it was only on TV.
The "Stargate" TV franchise — based on the 1994 movie featuring Kurt Russell — starred Richard Dean Anderson of "MacGyver" for its first eight seasons. The series was notable in having two separate Air Force Chiefs of Staff cameo as themselves, Gen. Michael Ryan in "Prodigy" and Gen. John Jumper in "Lost City, Part Two."
The central premise around the series was that the Air Force had acquired a "stargate" that was set up in Cheyenne Mountain. The team led by Anderson's character, SG-1, was pretty much carrying out a mission similar to of the Army Special Forces: building alliances with native populations.
The adventures eventually took SG-1 all the way across the galaxy and beyond, where they not only faced off against hostile nations, but also made contact with friendly aliens and acquired new technology.
And as is the case with special operations forces, SG-1 had gear that average grunts didn't get their hands on — usually. In addition to all the alien tech, they did get some earth weapons, too. Notable among them was the P90 personal defense weapon from FN Herstal.
The P90 is a select-fire weapon that fires the 5.7x28m cartridge. It is a compact weapon with a 50-round magazine. The gun made its combat debut during Operation Desert Storm with Belgian special operations troops.
You can see a video about this PDW that has gone to other worlds below.