HorseSoldier
Member
I have seen a colonel from Civil Affairs walking around with a Glock in a chest rig, though, so I know they've been used in service before.
I can think of at least one unit that carries them as standard issue.
I'm also aware of at least a couple cases where SF teams or other SOF guys managed to acquire enough of them to equip a full team down range through official channels (checked out from the JOS warehouse or similar).
So it happens, occasionally.