Ah, the 30 Herrett. Man, but there used to be a lot of those at IHMSA shooting matches until the 7mm TCU took over top spot. Brass is made from 30-30 Win and from what I remember is a pretty hot little round. You should be able to get around 2000fps or so with a 125 grain bullet out of that 10" barrel. Do not, repeat do not forget your muffs.
It was the brainchild of a guy named Steve Herrett and a gun writer named Bob Milek. Herrett is more famous for his Herrett grips. Steve is long dead, but Herrett grips are still being made in Twin Falls right here in Idaho.
I hope that you got forming dies with this thing, but if not you can still buy them from RCBS and Hornady I'm pretty sure.
Let us know how it shoots. It a fine deer round if you keep your shots at a sane distance. Topped with a good scope, it should be fine out to 150 yards or so, with 100 yards being better.