Whenever I play with the mod the character and hands and guns disappear? Please help!

Just Optifine things. I have fixed the error in recent versions but at the cost of preventing the scopes rendering their view.

After restarting the game my character came back but when I applied shaders I got error 1282 when zoomed in and 1284 when firing

Are you using the beta version? If so, download the full release.

After uninstalling Optifine, mod just works properly.

I meet the same problem, shooting while screen shows some kind of texture file. And after that, all entities' models including players, animals, chests, and even my hands will disppear. Restart game or my PC cant sovle such problem. And I'm sure I installed the full release.