The Red Hair Pirates. A mix of mystery, badassery, haki, sake, and guns. I’m proposing an idea about their guns. They use Haki in them.
I personally believe that this is going to be a theme of the Red Hair Pirates, in the sense that their crew is themed around Haki, Firearms, and Sake. I say this because:
•When Lucky Roo got involved with the rescue of Luffy, he shot and killed a pirate using a flintlock. This was back before we knew much about the show, but now that we’re farther, we haven’t seen much ‘end-of-series’ level sniping.
We haven’t seen someone imbue Haki into a flintlock pistol or rifle, and that is why I think Shanks’s crew is powerful for that.
•When we saw Benn Beckman in Marineford, he pulled a gun on Kizaru and made him momentarily stand down.
•When Yasopp saw “God Usopp’s” bounty, he was laughing his ass off, but he was also seen hoisting a rifle on his right shoulder.
The first 3 crew members we are introduced to, and we are shown they all use guns. On top of that, we learn a bit about Haki and how it worked (very partially) from the Rusukaina Kingdom (Amazon Lily), so the fact they are introduced around the same arc is important.
To add to this point, there isn’t much of anything that can damage Logia outside of Devil Fruit circumstances or Haki, so as far as we know, it could be both. Lucky Roo is the one responsible for retrieving the Gomu Gomu no Mi, and Shanks seemed to be worried for Luffy’s sake because he ate the fruit. Perhaps that hints at an underlying theme between Shanks and Blackbeard; Haki Vs. Devil Fruits.
Haki Imbuement & Guns
Honestly, I think Haki Imbuement for guns would work very similarly to how Haki Imbuement works for swords. Adding it increases the durability, functionality, and strength of said firearm.
*Theory by fruitgodder