The expression TO SHOW ONE’S GUNS means to show one’s muscles or probably flex one’s biceps:
He isn’t very smart, but he keeps showing his guns to everybody.
Let me show you my guns. So, are you afraid of me?
I don’t like athletes showing their guns because mine hardly exist.
He was standing before a group of girls showing his guns and waiting for applause.
Show me your guns. I want to know who I’m going to hire to do the job.
Here’s the video version of the article: