Fixing the Dropship gun
Introduction
This article explains the process of fixing the Dropship gun's broken rotation in Source.
Fixing the Gun's Rotation
Copy the contents of this page, (courtesy of GRAI+) and use it to replace src/game/server/hl2/npc_combinedropship.cpp
— You're done!
Alternatively, if you wish to edit the code, the main change it does is add these two lines at the top of CNPC_CombineDropship::UpdateContainerGunFacing, immediately following the assertion statement:
m_poseWeapon_Pitch = m_hContainer->LookupPoseParameter("weapon_pitch");
m_poseWeapon_Yaw = m_hContainer->LookupPoseParameter("weapon_yaw");
Tip:If you're developing a Source 2013 mod, you could opt to use a community repo, and have bugs like these fixed by default.