Terrific. I just kept reading with the action & forgot I might review. Had to read it a second time. Liked the characters and dialogue very much. Think you could expand on these guys and the Vindication to do more stories. Would love to see some "psycholological" stuff between Pat and his brother. Now some remarks:
par 1: I think you should make it "Deep in thought, he squins his eyes...and then leave out "Or" which begins next sentence.
Par 2: I think this guy (Pat) would say
"shootin'" and "gainin". Don't you?
Par 3: I think you need to clarify who the speaker is here. Is it Jack or Pat. I know the next paragraph explains, but I think the reader wants to know while they are reading the dialogue.
Par 4: As an adjective to "course" you need to write head-on.
Loved this one!

LOVE THIS. Extraordinary writing (not that I expected any less) with a historic base. It's almost unfair, the talent for writing you have. ^__^ I look forward to more of this one.

This is cool. It's kinda like Master and Commander. Keep it up!