CRT Operations Practice Test 2026 – Complete Exam Prep Resource

Mortars that rely on rotation from rifling arm their fuzes as they spin in flight. The 4.2 inch round is spin-stabilized and won’t have fins, so the clearest sign it’s armed is evidence that it has engaged the rifling and begun to rotate. Look for land and groove scoring on the rotating band—that pattern shows the projectile has been driven by the barrel's rifling and achieved the spin needed to arm the fuze. Other conditions don’t reliably indicate arming: a missing powder charge points to an incomplete round, a primer being struck indicates firing rather than arming status, and being out of shipping containers relates to storage, not whether the fuze is armed.