Very good video. Forgotten weapons is a pretty good source of information.
I had a shot at a converted p13 a while back. The seller didn't know what he had and it was up for sale as a butchered 303. So, "He who hesitates.......". Rather than grabbing it, I told him to check it out as I believed it was worth quite a bit more than the asking price. Then another buyer stepped in and picked it up. Chance of a lifetime and I hesitated.