In vanilla IV, Niko inserts two rounds which somehow fully reloads the shotgun. This mod makes it so that the correct number of rounds are inserted. Works for both the pump and combat shotgun. I am not an expert at coding, far from it in fact, and this is my first go at it so apologies if it sucks.

(Watch the video for a demonstration of the mod).

Update (v1.11): Now available in .net.dll, still doesn't work with iVSDK.net. I explain it in the gtaforums topic: https://gtaforums.com/topic/997958-proper-shotgun-reload-for-gta-iv/

Update (v2): Reworked code for IVSDK.net compatibility and other improvements.