My .684" balls are a bit undersize, but will work OK. A .703" ball would not fit in the case as that would not fit the chamber. An unsized MagTach case will chamber, but is a bit snug in the front 1/3rd of the case. The cases are listed as 2.4", however mine measure 2.450" which is close enough to 2.5" to suit me.

I loaded up 5 rounds in MagTech 16 bore brass with 3 drams (82gr.) of 3F, a few wads and .684" ball with the mouths crimped just over the centre of the ball holding them snugly due to the compression/springiness of the fibre wads. I lubed the fibre wads with my own BP soft mix of beeswax/olive oil. There is one 1/8" card wad on the powder, & 2, 1/2" wads between the powder and ball. I crimped the cases in a 12 bore paper-hull crimp starter, which is a smooth steel cone inside, no ribs. It is mounted in my old Herter's press - yeah, it's an antique - well, older than I am & I'm getting there. It will be cold when I shoot these and the soft lube may be necessary to help soften the fouling.

If I don't get out before Saturday, that will be when I try them. I suppose I should load up at least another 5 for testing, this time with 2 1/2 drams or 68gr. & of course, more wads to fill the space. If this was a modern gun, it would hold a healthy powder charge - at least 5 drams I'd think & would polax any bear I'd be likely to meet. I suspect 3 drams of 3F should deliver about 1,225fps with that ball, maybe 25fps more.

Lancaster, I bought a pound of Cerosafe and will get a chamber cast as soon as I polish my chamber a bit. It has a few rough spots I want to smooth out. Too, the brass will fit better once I get that done - nothing radical, mind.