For fun (and cost/availability), I've been playing with a few different cast bullets to see what works - some are too long for the magazine (eg. RN style), but I found a 240gr RNFP bullet recently that seems to work well. It's roughly the same OAL as my usual XTP bullet:
Tests showed that it fed reliably and (surprisingly) didn't lead, but I wanted to powdercoat/size the bullet anyway so I melted the lube off, PC'd and sized:
Loaded ammo with powdercoated bullets:
Slo-mo:
A full mag of 7 rounds:
The last case seems to have ejected then jumped back into the port - I may up the load a little to enhance ejection. I also, apparently, need to work on my recoil-control - Holy Wobbles, Batman...
These are commercial bullets, but my intent is to find the right bullet and then have a mold made so I can experiment with my own alloys and sizing - I think this design will do nicely with a few small changes. Also, my thanks and deep appreciation for the help of one of our fine members, dondiego.