When Samu Qureshi sits down in the middle of his 4,100-square-foot “museum” in Bethesda, the longtime Washington football fan is surrounded by his life’s work.

The G37 is a duty-size pistol, the G38 is a compact pistol, and the G39 is a sub-compact. The problem was not that the pistols or the 45 GAP cartridge were bad, but that no one cared. The thinking ...