I highly recommend Buffalo Bore Company's heavy .44 mag ammo (they are a bit pricey though). Because Marlin still uses a very slow twist (1:38) in it's .44 barrels the heaviest bullets that will stabilize are around 300 grains, sometimes more, sometimes less, it depends greatly on your particular rifle. Either hard cast or jacketed soft points are a good choice, but I believe that the Partition bullets are available in .44, another good choice. But keep in mind that hogs aren't bullet proof and a well constructed bullet at normal .44 mag velocities will put even large hogs down quickly and cleanly.