Straight from the shoulder

Watching a 1930's movie, and a gentleman described a conversation he had with a local political official as " I had to speak to him straight from the shoulder". I assumed this ment "straight talk", but what is the reference to the shoulder?

The reference, I think, is to a punch coming 'straight from the shoulder' - that is, with the maximum force; with all the deliverer's strength.

DFG