Some Pedersoli shotguns that are marketed 12-gauge are actually 13-gauge and sometimes the choke constriction doesn't match up to what it says. Ideally, you have to measure the bore and choke, or you have to pattern it and figure out what the choke is. You should not shoot steel shot through a full choke regardless. Many Pedersoli's are marked 18.3 (mm) which is .720. That is nominal for 12-gauge as most conventional 12-gauge start at .729 and go up from there. I've seen 18.5 on one, and that would make it right at nominal 12-gauge. Then you have to look at chokes. If you put a choke gauge in either of the aforementioned barrels, you'd get a false reading. If the 18.3 barrel reads .010 constriction, It's only SK-IC, although a gauge would read .710 and Mod-Full. So before you buy anything to make cards or wads, you should have the gun in hand and assess what you really need. A bag of 1000 over-shot cards is about 2-cents each. You could just use those and each shot would be about 8-cents if you put 3 over powder and 1 over shot. You still need to get the right size but they will easily push past any choke constriction if you start them on edge. Even the over-powder cards or "nitro" cards will go past chokes if you start them on edge and worst case you might need a short starter. You could just use "nitro" cards too. One or two over powder and a half of one over the shot. They are about 4-cents each, but you only need 1.5 to 2.5 to load, so actually a tiny bit cheaper than using the over-shot cards exclusively. Regarding steel shot, you can use a shot-cup if you want to. I've tried this and decided against it but here's what worked for me. Load and over-powder or nitro card on top of powder, then a lubed shot cup and you need a short starter to get it in. Then shot and a card on top. I have found Bismuth to work better at the velocities we get with BP. The steel seems to need a bit of velocity, and a bigger pellet size. #5 or #4 Bismuth has readily dropped ducks, geese, cranes and turkeys for me.