http://accuratemolds.com/bullet_detail.php?bullet=34-300D-D.png
Where would a guy even start with load data with this cartridge and cast?
Easy, with paper-patched bullets:
1. Refer to copper-jacketed, lead core load data of similar bullet weight to your cast bullet.
2. Pick the slowest powder listed for that bullet, or nearly the slowest.
3. Start with the starting load data given, or back off a little below that and make it up with lightly-stuffed Dacron.
4. Once you get that established as safe and have your powder volume particulars in relation to the case body/shoulder junction, we can discuss how much to reduce the load for granulated poly buffer.