RE: Cast bullets for 30-30
Straight WW is a pretty good alloy, fairly hard. IMO your GC question depends on how fast you want to push the bullet. I can push WW up to 1800 fps without a GC. I use a slow powder to do this with. A lot of people say 1600 fps is as high as you can go, but I have done 1800 fps without heavy leading(you will get some). I just make sure I have a good polished bore(all the jacketed material out) before I shoot the first shot.
Over 1800 fps you will need a GC. Tom.