This file has everything you need to probaly find the issue
https://drive.google.com/drive/folders/18ZdVp4fPzKg5bDfTIwfrGTQwVUlrZAAC?usp=sharing

Hey, I came here for the exact same reason, however I realized I had one thing had changed recently in my modpack, and this was adding in the The Official Connected Textures Pack resource pack. Upon removing it, the barrel is visible once more.