Doesn't seem to work at all in multiplayer; clients can spawn and use the weapons themselves but no one else can see them, and if they rejoin the game, they're gone from the inventory.

The only complaint I have is that massagers seem way too durable considering that they're, well
massagers - though that's more a balance issue than anything else.

When you load or rack the o/u shotgun the model turns into the vanilla d/b shotgun.
Can you check this out please?

I got the reloads using the proper shotgun models now. Should be coming in the next update.

Found an M249 and M249 belt in a safehouse, but when I try to reload the M249, my character just enters the "Surrendering" pose and the reload either doesn't happen at all or takes longer than several hours (I fast-forwarded for a bit). Is that intentional?

no that means I probably missed a file somewhere, is it on b41 or 42? and is it a preexisting save or a new one?

tried recreating that issue, couldnt find it. did you have any other mods enabled? sometimes i fixed my issues when testing weapons by completely restarting the game

I have a whole bunch of other mods installed - here's a full list in a pastebin.

https://pastebin.com/xsUpL8MH

Went back to the save after restarting my computer and I still have the same issue.

Made a new save with *only* "Cheat Menu: Rebirth [B42]", GTA Guns, and GTA Custom Magazines, and I still experience this issue.

I found nothing that comes close to interfering with the anims files I added. If it still happens after you made a new save, double check that your game doesn't boot with mods enabled.

In the main menu at the very start where you get the options to continue/load/solo/multiplayer etc, click on "Mods" and make sure nothing is enabled, anything that is enabled in that screen will be enabled on game startup and can mess with other mods even if it is disabled when creating a new save or loading a save with different mods. And double check mod load order too just in case.