Version 41.73
Singleplayer
No mods.
Replication steps:
When reloading the MRS788 the character ejects the magazine, reloads it and inserts it again instead of loading bullets into the gun. The MSR700 does function properly.
I managed to fix this by changing the lines
MagazineType = Base.308Clip, to /*MagazineType = Base.308Clip,*/
and
GunType = Base.HuntingRifle, to /*GunType = Base.HuntingRifle,*/
in items_weapons.txt. With the changes it behaves properly, just as the msr700