It's a good video. He seems to grasp at some things like assigning letter guns A-L to 1959 and M-Z to 1960 though. I've never seen any evidence that shows that at all.
Seems like he's trying to break it up into two equal production years-- first half of the alphabet in 1959 and the 2nd half in 1960. Personally, with only 20k attributed to 1961 (6th year), It seems possible also that some letter rifle production may have occurred in 1961.
If anything, it makes far more sense stock serial size (small-font-vs-large-font) would be the dividing line for chronological order of production-- which has no basis in alphabetical order.
Given the very low 3 year production total for 1959 thru 1961 there is also the possibility of a prolonged halt in production. Just as the serial data show for the type53 and type54. It would be interesting to see the AK56 serial data for that time period, too.
Overall he has a pretty good grasp of things, it would appear he's using Chinese sources based on his exact serial numbers assigned to the ghost gun demarcation along with exact production #'s for years 9, 10, 11, & 12.
I was wondering about this too. I thought ≈530k was the highest known yearly total for Type56 production (11th year).
Perhaps his numbers are from Howie's serial number thread?