Aut cum scuto aut in scuto
You know we wouldn't dream of sending men into combat with a weapon they never fired for real or only fired in practice with simulators. We don't do it with riflemen, machine gunners, tankers, etc. I wonder how many of those guys firing TOWS and other missiles had never actually fired one. I could see the difference just 2 years later as I watched Marines engage an ambush. It was elegant.