The Orthogon parts from McShay Mod Pack are a bit of a mess, the upper has its own bolt that we never get to see due to it not removing the original bolt, they leave a gap when used with other receivers, and they're a bit "too far forward," so to speak.
Goes in mod_overrides
Changes:
Spoiler!
The AMCAR now uses a detachable carry handle with the upper equipped
The ejection port on the upper is larger, probably wasn't necessary but I always thought the scrunched up ejection port was weird
The standard bolt was removed so the built-in one can be seen
The receivers now properly aligned with other receivers, and they no longer partially clip into some handguards
The AMR-16 now uses Cynosura Iron Sights with the Orthogon Handguard equipped
New black market icons that are more in line with the older black market icons