Beverly Crusher just happened to have one in "Conspiracy" after the parasite-possessed Admiral Quinn managed to incapacitate Riker, LaForge, and Worf.
Crusher just appears to pick up the gun dropped by LaForge when he flew through the doors. Or at least that
gun is nowhere else to be seen, even though Burton was still holding it when hitting the doors...
Actually, I think they did appear on Voyager once. Can't remember where though.
That would be "In the Flesh", where Chakoteya recognizes the concealed-carry potential of the type and takes it with him to the Species 8472 dome.