The only drum I have first hand experience with was for a .22 semi, and squeezing rounds off too quickly made it jam up. Not that a .22 is a .223, I know. I would think the heat build up after the first 20-30 rounds would be significant.
There are a couple of YouTube videos out there of full auto M-16 “meltdowns”, firing them as quickly as possible until the weapon fails. It usually happens at well over 1,000 rounds. That’s using both drum and standard 30 round magazines.
L