Bullet casting makes it easy to experiment, if you have a tolerant mold maker. Accurate Molds supplied this one at my request: the 31-091H.
It is for the .30 Luger. My pistol has 0.312" grooves, with 0.304" lands. The little cartridge has a quite short neck, and the bullet nose needs to be short enough to allow an unfired cartridge to extract freely. Yet, the original loading was for a 93 grain bullet. No problem with a FMJ, a bit tougher with cast.
My solution was a standard nose profile, with a single lube groove centering the case neck, and 0.090" of bore riding base to add weight. I confess that the only reason to make the base bore riding instead of full diameter was curiosity. I just wondered if it would work.
I can say that it does work well, in my pistol at least. After lubing, I rub the bullet base on a paper towel, and then twirl an empty case (with the neck sized to a slip fit) over the bore riding portion, to remove all excess lube. Loading is then straight forward.
I'm interested in target shooting, so my loads have been light ones (3.0 grains Competition, or around 3.2 grains Bulls Eye) - both measured via a RCBS Little Dandy rotor #4. There is no leading, and accuracy is as good as any other bullet which I have tried.
So, you can have a bore riding base, should the urge arise. Now, I didn't say that you need to. Cast on! - have fun.