I liked this story.
In my opinion you can tell a story but there are some mechanical issues you need to work on.
This piece is so long it's going to take me some time to go through with a line by line critique. I'll do it because this feels like an honest effort by someone who is talented.
I will say now, that you violated Chekov's Gun rule. 'If there is a gun on the wall in the first scene it must be fired in the second or third.' This is to say: eliminate all unnecessary dramatic elements. I see the juxtaposition of the title with the pistol in the old mans pocket, but I was still hoping he would shoot it before the end.
I'll have more suggestions by the end of the weekend when I'll have more time to think.
Thanks for posting this, and again, welcome.