As I read through the thread, I saw that others had called you out on your errors later, so sorry for the duplication. The fact that you were an order of magnitude off on the weight led me to the assumption that you had never touched a cartridge before.
I was basing it off of my experience with a very heavily-constructed AK47 and no actual empirical evidence as to weight except for my experience lifting weights in the gym.
My point overall was that from a practical and tactical perspective, a drum mag isn’t useful for a single shooter. Drum mags are great for laying down covering fire, but picking off moving targets requires a little more agility than that weight would particularly allow.