AR-15 / M4 / M16 Lower Receiver

AR-15 | M4 | M16 Carbine Lower Receiver with Semi-Detailed Internals for Gunsmith-Features in Games.
Outside of Weapon Customization Features, non-visible interior Geometry (Hammer, Springs, etc.) can be removed to save render resources.
For further customization small parts geometry can be removed and replaced with custom Objects (Fire-Selectors, Bolt Catches, Mag-Releases, Trigger Groups, Takedown Pins etc.)