There is a pretty popular gun shop / shooting range near the Charleston Prototype. I even got my shooting ribbons there as a student. They have everything you little heart desires, including fully automatic weapons. Although they cost a lot to rent. As far as during your actual time at sea, not a lot of opportunity. However, I have heard of a couple guys on the ship (Carrier) got there gun quals. Mostly they had to get permission and have everyone buy off on it, but they did get qualified on the M60 and .50 Cal. Mostly it depends on who is in charge and if they feel letting you or not. I wouldn't count on it though.