Purchased a Marlin camp nine earlier this year and I was interested in possibly shooting cast thru it. Some fellows say that the Micro groove barrels and cast bullets don't mix well. Would like some input from some more expierinced casters/shooters
Cast boolits work great in Microgroove barrels if they are sized to the barrel. I shoot 30-30 and 44mag with Microgroove barrels. I size my 30-30 boolits to .310 and my 44's to .432.
For your 9mm you might have to use .357 or .358 cast boolits.