I have been looking for these wads bought some from oxyoke says they are for 54,56 and 28ga. They are 56cal so worthless for me. They need to be 57cal to work in a 56cal. So I started trying to see if I could come up with a punch. I found that the inner diameter of 1/2 series M copper tubing is .569 I got a cone grinder for my drill and ground the inside of a 1/2 inch copper tube to make it sharp and with a hammer and block of wood have been cutting them from cardboard and from 1/8 inch thick lubed 12ga wads I had. They look good will try them out in the morning. One fella suggested using washers on hard felt wads with a small C clamp and cutting them with something like a sharp hobby knife. Might try that out as well.
Copper pipe, not just for plumbing anymore! When I first started on my Black Powder adventure I made up some speed loaders using 1/2" pipe soldered to a 1" to 1/2" reducer (pounded to fit my 15'16" barrel) which I thought would be very cool. The only problem was I had to set the pipe on a rod and jam the barrel down on the loader, otherwise that darned powder would just fall out the bottom. Peer pressure and the fact it took longer to load made me abandon the idea, but I feel it was creative.
Chief
You might try track of the wolf. Here is the page that will tell you the size you need
https://www.trackofthewolf.com/List/Item.aspx/170/3
Thanks old salt. The problem is it falls in between what is available. You can get 24ga and 28ga but this is 26ga. My wads worked very well. tried 1/8 and 1/4 hard felt, cardboard in various combinations and 60 to 75 grains of FFG in 5 grain increments. The 1/8 wad with 65 grains of powder did not do to bad but I think the best load I tried out was 75gr FFG triple seven with a 1/8 hard felt wad and a overshot card then a 28ga shot cup and 1oz #6 with a over shot card on top. Used my wads to shot a .550 ball also, no patch. I was surprised how well the ball shot. The shot loads I tested were all fired from 20 yards.
if there is any place that knows ahotgun wads for muzzle loaders it is Circle Fly.
http://www.circlefly.com/html/wad_sizing_chart.html
The 28 ga wads at .585 will probably do just fine, even though they are meant for a .550 bore.
There's a fellow who goes by "Ohio Ramrod" who will make a punch the size you want. If you want his contact info, send me a private message.