i got this crash as i got near the ship that spawns the attack Helicopter i was using optfine i know not every mod dev supports optfine but i wish i could at least disable the helicopter as a temp fix but its not a option.

mc 1.12.2
forge 2838
techguns-1.12.2-2.0.1.2_1
OptiFine_1.12.2_HD_U_E3
crash-2019-06-28_19.15.11-client.txt

Same issues happen only solely server.

It's an optifine problem, and no I can't add options to disable every single feature of the mod, this is too much work. Also other .obj models (grenade launcher) could crash too. Short story: Optifine is not supported and never will as long as it stays closed source.