I used wax bullets and .357 magnum cases with small rifle primers in a Marlin 1894C. It was a lot of fun, but yes they are pretty loud, and the primer smoke is pretty unpleasant after a few rounds. The cartridges didn't feed reliably in the lever action either, I had to insert them one at a time in the chamber.
It was fun, if you shoot a plastic water bottle, the wax bullet would end up inside of it, and you could reuse it over and over.
We shoot the colibri primer only .22 rounds in the basement sometimes, out of a .22lr rifle they are so quiet you hardly know they are being shot. Significantly less loud than an air pistol, but the colibris sometimes don't make it out of a rifle barrel, so you have to be attentive and check the bore when you're done.