I don't know any active duty service member that would confiscate weapons, either.
They do it in the desert all the time. It's been established in the past that there were Marines who would kill Americans resisting gun confiscation. This was a question on a 1994 survey. Unfortunately the only website I can find with the complete text drifts into kook territory, but here it is:
United Nations
Edit: Here's some more info:
http://thefiringline.com/forums/showthread.php?t=37575
The man who wrote the questionnaire feels there would be a "Complete unit break-down" if Marines were ever ordered to fire upon gun-lovers, but what concerns me is there are plenty who would do it if they could.