R. Lee Ermey, the sergeant in Full Metal Jacket, answers mail about what the armed forces were, and really are, like. He steers a WWII M5A1 tank and explores the Gatling Gun and samurai swords.

What are the different pieces of a Knight's armor? What's in a WWI backpack? What's inside a Landmine?

Can a bullet can penetrate body armor? How accurate was a medieval crossbow? How did WWI pilots shoot through their propellers?

How did Civil War Cannoneers aim their artillery pieces? Exactly how does night vision technology work? How do you clear a minefield?

How do you operate a Landing Craft, Air Cushion (LCAC) hovercraft? What kind of saddles did the Cavalry use in the Old West? How do Gas Masks work?

Mortar; World War II G.I.'s personal items; American Indian arrows.