I'm not seeing them come up in shops. In single player or multiplayer. Do you have to start a new game from scratch?

引用自 Troy：

I'm not seeing them come up in shops. In single player or multiplayer. Do you have to start a new game from scratch?

Afaik, you don't have to start over. But, crossbows seem to be pretty damn rare in the game, and since there are lots of them, you either need mods that expand the merchant's inventory (such as The Adventure Mart) or just be pretty lucky and check merchants regularly.
I'm using Synergies and lots of addons, so I have unique and legendary merchants and they do sell them. Normal merchants have them too, sometimes.

TL;DR: No reset required, they are just rare (just how crossbows are treated in the game :S).

Thanks very much! I will look into the Adventure Mart mod, looks like a nice addition actually. Thank you for the response.

Also consider Smarter Gambler for those who also want the blue and above stuff and don't want to play Synergies.

I noticed some other projectile mods also have problems hitting mobs from above and on slopes; It's like the mob's target is shifted away from the projectile's path.

I've been thinking maybe- if the projectile was given a "homing" function OR if the projectile-to-target simply needs an adjustment in position?

yup... more theories ;)

Ah yes, homing. I'd love to make the projectile homing but I think of it as a bit cheaty. One possibility would be to have some unique and legendary rifles with homing missiles.
(I feel like I should point out that making a missile home is just changing one property, so no big deal whatsoever.)