Quarterly Firearms Training
Gun safety should be the top priority of any job where you have to use one. The FBI are smart and know this, which is why they have their enlistees take quarterly firearms courses to make sure that their skills are up to par. No mistakes can be made when handling a firearm.
When they start the training, they are only allowed to use a fake gun. Then, they move up to a real one that they can reload but isn't active. Then, they get their operational gun. By the time they graduate, students have fired over 4.4k rounds from a Glock 19M, 620 rounds from a Colt M4, and 127 rounds from a Remington 870.