Sabotloader, wouldn't just cutting the petals off a .45 sabot be the same thing as a sub base? Just seems like that would be better than any over powder card or veggie wad for sealing the bore on firing. Especially with the harder solid copper or brass bullets that more than likely wont obturate quickly. There is no need for anything when I use the full sizing die but the smooth sizing die or, just knurled to fit, will leave a lot of gas leakage until or even if the bullet obturates.