Two diameter GG bullets

[Kurt]

You can use a GG or use a what was called a ringed gullet that is bore diameter. It was common practice back in the 1800's. I have seen bullets at collector shows that where loaded in cartridges side by side. They react just like a PP and performed like a groove diameter GG from what I found using a .447 diameter soft postell GG in a .45-70. It gave me a little more leading being a little undersized but when I put a knurl on them to expand them to .451" they shot great.
Remington also had a hollow based bullet, not quite as deep of a base but a very thick skirt that looked similar like a mini that had 2 and 3 grooves that they seated right on the powder charge.