What is "to club a musket"

Club \Club\ (kl[u^]b), v. t. [imp. & p. p. Clubbed (kl[u^]bd); p. pr. & vb. n. Clubbing.]

1. To beat with a club.

2. (Mil.) To throw, or allow to fall, into confusion.

   To club a battalion implies a temporary inability in the commanding officer to restore any given body of men to their natural front in line or column.
   --Farrow.

3. To unite, or contribute, for the accomplishment of a common end; as, to club exertions.

4. To raise, or defray, by a proportional assesment; as, to club the expense.

   To club a musket (Mil.), to turn the breach uppermost, so as to use it as a club.