Different guys for different things. You have to be more specific.
Rustywoods, Ellwood Epps, Buffalo Arm, ....
EE is often best if you wait long enough.
Does anyone know a good source for hard to find, antique and obsolete ammunition and casings.. Does anyone "know a guy"?
Bruno Gross in Fairview AB (780) 835-4648 is the guy I went to for 8x57R, 6.5x54MS and a couple other oldies. that was a few years ago, hope he still sells hard to get stuff.
I have most reloading components for the calibers I'm looking for just running shy on brass. along with factory ammo. Not one for collecting I need shooters.