Took a few weeks to finally get here but I finally got my wad punch for the 8 gauge. A few weeks ago I started browsing for wad punches or circle punches, there seem to be alot of different styles and names depending on the seller.
I was beginning to think I wouldn't find a size for the 8 gauge, the fiber wads and overshot cards you buy are .850". I have seen 7/8" wads used in 8 bores rifles but those have much thicker barrels and dont have to worry about being squeezed through a choke. What I found is 21.5mm is what you're looking for I've read tolerances for machining put the punches diameter at .846-852" etc which seems perfect to me.
There's a few reasons I wanted a punch, in Toms book I think he mentions felt seals better in the bore than fiber wads and also they don't confetti out the muzzle. Another point is I use 3/4" of wadding in my 2 1/4oz loads, the fiber wads come in 1/2" sizes. While they are easy to split they are always slightly different or inconsistent. The plan is to use three 1/4" durafelt wads so I will have a better material and the wad height will be the same each time. The last point is I dont like the looks of the plain white overshot cards, I will probably get some stamps made so I can mark them to how they looked back in the day.
I did some testing with some thick green paper I had on hand, they appear the same diameter as the white ones I bought as you can maybe see the green one overlaid on a white one. I think its going to work out as intended not bad for the $9.99 I paid
. I was surprised it actually came in a decent little case.