DGR-

Slug and measure your barrel.
Post to us here what your bore and groove diameters are, and what rate of twist your barrel is.

From there you'll no doubt get level-on advice on how to load for your new rifle.

Bore rifles are distinctly a class upon themselves, the rifles typically unique of all others.
You'll be best to load for your rifle, it's easy and cheap to do, and you'll get consistent, powerful, and accurate loads.
To put it simply, bore rifle shooters are handloaders.
You'll almost definitely need to make your own ammunition.

...and you'll LOVE it!

--Tinker