US Marine Corps FMF CORE Weapons Fundamentals (109) Practice Test

The essential safety idea is that the safety pin keeps the grenade from arming by locking the lever (spoon) in place. Until the pin is removed, the lever cannot release the firing mechanism, even if the grenade is handled roughly. Because of that, the safest and most universal rule is to leave the pin in until you’re ready to throw and have a clear path to your target. Once you remove the pin and still hold the lever down, you’re preventing the fuse from starting; the fuse only begins after you release the lever, giving you a brief delay to throw. The other statements either misstate how arming works or reflect practices that aren’t the primary safety rule—for example, the spoon isn’t removed or kept pressed after arming.