To Reproduce
Steps to reproduce the crash:

1. start the game
2. load in a world
3. go to the guns section
4. and last put the gun in your hand

Screenshots

Versions (please complete the following information)

• Forge: 1.12.2-14.23.5.2838
• Flan's Mod: 1.12.2-5.5.2.

Crash Log
<
crash-2021-01-05_16.09.23-fml.txt

Additional context

I am still very new to this so I don't know where to put the patchlinks

I downloaded version 5.6.0. and the game didn't crash when I hold the weapon