This is an old discussion, but has never been totally dismissed or agreed on. If all things are equal, Alloy used and bullet to barrel fit. I believe lack of bullet obturation to be a factor in barrel leading, with bevel base cast bullets.(gas cutting). I have been in many discussions over the years, some with bullet manufacturers at gun shows, with those that mass-produce bevel base bullets for retail sale. I do not pretend to be an expert at casting, all though I have cast and shot cast bullets for years, and I also know the bullet lube plays a large part in sealing gasses of cast bullets.
It just seems reasonable to me, that the design of the bevel base bullet, cannot obdurate to the point of sealing a cast bullet at its base, thus promoting gas cutting.
But then there are those that do not believe obturation occurs in cast bullet. The reason for this inquiry, I read an article in Handloader titled Cast Bullet Myth Busting By Mike Venturino. Mr. Venturino is also of the belief that cast bullet obturation is a natural occurrence with cast bullets, but never got into the Bevel base bullet discussion in this article. An article I once read on the subject suggested commercial casters made bevel base bullets for their convenience in commercial casting machines, they are simply easier to mass-produce. And pass the bevel base bullets on to shooters as a seating benefit; knowing they do in fact promotes leading.
But then this is my opinion on Bevel Base bullets, what do you think. And I do not mean to step on anyone’s toes; these are my beliefs and opinions. Formed from Articles I have read over the years in casting books and magazine articles and personnel experience with these bullets..