.30 carbine is noticeably weaker than 8mm Kurz, and both the weapons (Both Mkb family and VG 1-5 compared to the US Carbines) and cartridges were designed with different purposes in mind, I feel them being different is entierly justified. Think of .30 Carbine as a overgrown pistol round and 8mm Kurz as a stunted rifle round, they are approaching each other but still fundamentally different.
Well, as you know already, I’d like to remove the RoF upgrades in their entierty.