As I recall that gun was zeroed with a .610 ball and used 125 grains of 3F. But I made it years ago, so I can't be sure of that info. It's got Forsyth rifling and may even take a 620 ball but it was too long ago for me to remember the details. The man who owns it has never killed any big game with it. He got the gun shortly after getting married and starting a family and never has found the time to take it hunting. That in fact is the reason he called me to ask if I has anyone on the back-log wanting one like it. I told him "no, but I will put the information out and ask shooters to pass it around."
My back-log for custom ordered guns ran between 6-8 years for about the last 30 years or so, and getting the word out that one of my guns can be purchased without the wait may motivate someone to step up and buy it.

But I am just the guy who made it. Anyone wanting to know the smaller details should e-mail the owner.
What I can tell you is that it was very accurate and speaking for myself, I'd not hesitate to hunt any game with it, up to about 1500 pounds.

flyingzebraranch@gmail.com