Ok, after reviewing many articles, books, and phone calls I have still to find a definitive answer, or have I? It seems that high velocity (2100 f/s and beyond) is possible but certain factors have to be in play. !, the right boolit design has most to do with the success of such a venture. The Lee boolit moulds that I have do ok but groups are something I'm working on. I have a RCBS 30-180 SP that has plenty of grease grooves. This seems to be the trick. The bore ride designs appearantly either want to yaw in the bore or run out of lube. They can do both.
I think the proper lube is in order here too. I am going to develop a parafin/lithium grease/lomy combination to deal with the stresses placed on the alloy. I am using 50/50 beeswax alox. No real problems with leading but accuracy can improve. I have used teflon tape to augment the aformention lube with great success.
So, I think also a spotlessly clean bore has a huge factor in leading. I've actuall disolved lube on a patch and prepped the bore with the patch. So far so good.
What I want to know is what's been your experience? My goal is to get a .308 to cycle through a M1 Garand. Got the cycling done w/o leading. Now I think it's a matter to matching up the right propellant to the job.