Thought I'd just give a quick heads up in case someone encounters this same issue.
When "Curses!" and HWG is loaded into the same game, reloading with any HWG gun makes all bullets in the player's inventory disappear and does not load any new bullets into the gun. Cool mod though, I really love it.

"Curses!" Link:
https://www.curseforge.com/minecraft/mc-mods/curses

P.S. This is with the 1.17.1 version of HWG and "Curses!"

I'd suggest opening a ticket on there side as well, I don't see anything that be causing the issue honestly outside this issue HyperPigeon/Curses-#2 though it looks like the mod author isn't maintaining that mod anymore.

Do you have any active curses?

Not at the time of testing it. The mod simply being active caused the guns not to reload. They never had the curses on them and no curses were active to my knowledge.