In a military "weapons drill", recruits repeat the same handling steps until they're automatic. What is the actual purpose of this kind of drill?

Drill builds routine, and routine frees up mental capacity in action — when the manual handling runs on autopilot, the brain is left free for the situation that actually needs judgement.

The instructor's blunt version: repeat the handling "until your fingers are raw", again tomorrow and the day after, and "then you won't need your head for it — you'll just function".

The deeper reasoning:

• Drill → routine → thinking capacity (Denk-Kapazität). Automating the mechanical part is not the opposite of thinking; it's what preserves thinking for where it matters.
• A scarce resource under stress is attention. Anything you've made automatic is attention you get back for the unpredictable parts of the situation.
• There may be several correct ways to handle the weapon, but one is fixed by regulation as the right one — uniformity makes training by a militia feasible and is itself liability-relevant.

So drill isn't mindless in effect even though it's mindless in execution: its whole point is to make room for the mind elsewhere.

Tip: This is the same logic behind any expert's automaticity — a surgeon's tied knots, a pilot's checklist flows. Offloading the routine to muscle memory is how experts keep cognitive bandwidth for the genuinely novel.