For the veterans,  what does"lock and load" mean in the movies such as Platoon?

Lock your bolt back, load a magazine, release bolt and chamber a round.

It means get ready to get some.


- rem

Quoted: Lock your bolt back, load a magazine, release bolt and chamber a round.

Per:
Wordorigins www.wordorigins.org/wordorl.htm#lock%20and

This imperative phrase originally referred to the operation of the M1 Garand Rifle, the standard U.S. Army rifle of WWII. Its meaning is more general now, referring to preparation for any imminent event.

The original phrase was actually reversed, load and lock. The phrase refers to inserting a clip of ammunition into the rifle, loading the clip and locking the bolt forward, thereby forcing a round into the chamber. The phrase first appears in Gach's 1941-42 In the Army Now. It was immortalized by John Wayne (who else?) in 1949's Sands of Iwo Jima, where the Duke reversed the phrase to the current lock and load.

Safeties on is implied.

I always thought it meant "LOCK a mag in the rifle and LOAD the chamber"

I always thought it meant, for the M1, LOCK the bolt back, LOAD the magazine.

John Wayne immortalized a mis-statement.

I thought it was a civil war (muzzle loader) term original with teh terms being load and lock.

Quoted: It means get ready to get some. - rem

+1
That is what it Really Means

I don't know about John Wayne, but the command goes back to at least the early 1600's if not earlier.

The commands are:
Lock - Lock back the lock (the spring loaded thing that holds the flint)
Load -  duh, load powder and ball
Prime - fill the priming pan
Aim - self evident
Fire - self evident

Since the invention of fixed ammunition the third command is no longer relevant.

In modern usage it means lock back the action and load the rifle.  Loaded means magazine and chamber.

on a range where your bolt is already to the rear, it means insert magazine fully, let your bolt go forward.  in the field your bolt is forward, insert mag and pull charging handle back and release.  different conditions, different things.  same idea.