I'm about halfway through the game and I'm wondering if there's ever a reason to use a different gun besides the Lancaster Repeater?

I would love to have any legitimate reason to use the other guns. I upgraded and customized all of them. But so far, I've found that using Express ammo and the Lancaster is strictly better in every way than all other guns in all hostile PvE encounters.

The double barrel is cool, and sometimes I use it when entering a house where I know people will pop up close to me, but that's only because I'm desperate to use other guns and I know the shotgun will technically work, even though Dead Eye Lancaster - headshot everyone instantly, would be more effective.

For hunting, I use the Bow with improved arrows for mid-sized game, Varmint gun for small game, and rifle for big game.

Is the only option to just intentionally gimp myself to use other guns, or are there any situations where other guns have any kind of advantage?