Powder/shot card diameter ?

[Tim Ault]

As I keep on researching and reading up on shot loads I fail to ever see the dia of the card . So in general how big over bore should I make them my bore is .615” would a 5/8 .625 punch work ? . I have a tons of material in the .100 thickness I can use I assume that is good for the over powder card but will need to find some stuff for the thinner over shot card .030 I’m guessing 

[Hungry Horse]

 Make sure of your bore diameter by measuring it before you start looking for a punch. Some bores are .615, and some are .620 diameter. Mine is made from an old (NOS) Belgian shotgun  barrel that is .625. So you have to get the right sized punch for your gun. I have seen many punches made from pieces on pipe, or steel tubing, but worn out hole saws work great if you take the bit out, and sharpen the edge once the teeth are removed.
 You just need them oversized enough for a tight enough fit that the shot column won’t separate when fired.

Hungry Horse

[Brokennock]

I use store bought 20 gauge overshot cards and they work in both my guns. One bore is .615 the other is .618
Cereal boxes, cigarette cartons, and such work well for overshot cards. I'm sure if you look around you can find a lot of packaging that usually gets discarded that is of similar thickness. I don't think the thickness needs to be super exact.

[Daryl]

Beer boxes up here (Canada), make good material for over-shot card material.
Measured my muzzle and it's .620".  I use commercial 20 bore stuff from Trackofthewolf.
They sell wads by the numerical measurement as well.