Here is the class name to it
If you want to add it to a unit, put this in its init
removeallweapons this; this addMagazine "8Rnd_B_Saiga12_74Slug"; this addmagazine "8Rnd_B_Saiga12_Pellets"; this addWeapon "Saiga12K";
There are 2 magazine types, pellets and slugs. Just repeat which ever (or both) as many times as you need in the init.