I've been using mixed shot from cut shells since I started shooting smoothies. Where I live there is no place to go buy shot by the bag. I used to be really into modern shotguns and stocked up quite a large pile of shells of various kinds. Now that I have sold most of the modern guns, and only hunt black powder, I've been cutting quite a few. In fact, if you remember those red 12 gauge turkey loads from the nineties that were called Activ, I still have a bunch of those and have been mixing that with no. 6 shot and 7.5/8 shot. All from cut shells. Haven't had much time lately but been trying to get out and pattern my loads here and there when I can. Last week I used this mixture in my .45 smoothbore, .56 smoothbore, and New Englander 12 gauge. I was using raw sheep's wool for wadding over the powder and over the shot. First time I've used wool and highly recommend it. Got good tight patterns at about 25-30 yards with each of them. the smaller shot seemed to spread out quite a bit but the larger shot was more concentrated to the center of the target. Don't know why. It would appear to be a successful pattern for most small game and birds. The last couple loads from the 12 gauge had a little bit of copper coated BB's thrown into the mix. When I get a chance to finish my testing there will be a range report on here with pictures.
I go to the local furniture and appliance stores and get a big box from out back, like a stove or dish washer would come in, and spray paint a few large dots on them for targets. Then off to the dump with my regular garbage when I'm done. Quick, cheap, and easy, and those heavy duty boxes will stand up to a surprising amount of patterning. I haven't found a downside to using shot like this, other than the time it takes to sit there cutting shells open. At the end of the day shot is shot i guess.