For people starting out they will let you shoot just about anything that is close and safe.
My first time I had two BP replica Colts, a Marlin lever action and an 870 shot gun.
People that run CAS events know how expensive a full setup can be and also know once you get started you’re hooked for life.
They were very nice to me and gave me a lot of help and advice. One man let me use his double action 12 gage so that I didn’t have to use the 870.
As far as 44 sp in a 44mag marlin,,, better have tools and know how to take one down. Mine throws a fit every time I have tried, I end up with two rounds coming out of the tube and its one B------- to clear.