My thought exactly. 800 rounds a minute is 13+ each and every second. Even with 30 round magazines, it would take much more than a minute duration to load 800 rounds. Having a drum raises issues of overheating if it was possible to press the trigger that fast for a complete minute.
That alone makes me question what else in this article is wrong. Personally, Ive had several of both caliber, until my surprise boat sinking, and distance is the primary factor for me.