jhalcott,
I'm wondering with that 1:16" pitch if you don't get enough spin at cast bullet velocities.
If you're interested in taking deer with a home-made bullet you might try paper-patching the same bullet you're working with.
People who are really into paper-patching get special molds that are a little smaller diameter to make room for paper. But, if you just want to try it out, the good news is you don't need ANY special equipment except paper that is 25% cotton.
Go to an office supply store and look for drafter's vellum, it's thin and strong (25% cotton). Next cast up a bunch of bullets with the softest alloy you can find. If using WW, just anneal them in the oven don't quench 'em. Cut out a bunch of patches from the vellum using a jig made from an old phone card (shaped like a parallelogram). Dampen the patches on a sponge, roll 'em round a bullet, twist the excess paper at the base, set aside to dry. Run dried bullets through sizer (you can size bullets prior to patching, then size 'em again with patches, this reduces torn patches). Clip off twisted paper tails. Load using regular jacketed bullet data, but bell case mouth, and use only enough crimp to take out the bell or crimp on crimp groove only.
With pure lead, you are limited to about 2200 fps max velocity as the atmosphere and twist can tear apart the bullet. Slightly harder alloys can be taken up much higher.
The advantage of paper-patching is you can use soft, pure lead at linotype velocities and beyond without leading. This might get you the spin necessary to stabilize the bullets.