I bought a batch of odds and sods from a cartridge room clearout for very cheap money. The downside of it (or so I thought) was that there were so many different types. Im no digweed so I bought them. Ill never notice the difference between them. There was 21g, 24g 28g in 7.5, 8 and 9 even some subsonics.
Went to a place around Castle Douglas where quite a few of us went and had a friendly comp... using random handfuls of absolutely anything in the batch I managed a second spot in the main 100 bird shoot and also in the compaq. I think too many people worry too much about the cartridge and not enough about pointing it in the right place.