CAMP THUNDER, Iraq — Sgt. Kurt Smith is spending his time in Iraq as a full-time medic and part-time historian. Many of the weapons that his unit, the 4th Armored Division’s 3rd Battalion, 16th Field Artillery Regiment, have confiscated belong in museums rather than their arms room, he said. There are two 1917 Webley revolvers, World War I-era British Enfield rifles, World War II-era German Mauser rifles, Russian PPKs and British submachine guns. “I’m a weapons enthusiast,” said Smith. “My dad was a weapons collector and he passed on some weapons to me and my brother.” For the past few...