Zero experience with either the 7.92 x 33 or the 7.62 x 39. I can't be much help in dealing with this class of rifle calibers. They intrigue me a bit, as does the 6.8 x 43 SPC--but not enough to spend cash on rifles or ammo. I have enough calibers to ride herd on at present, methinks.
I also haven't given much thought to running castings in gas guns. I do not enjoy "The Chase" part of reloading as much as I once did, and prefer to spend my "chase" time pursuing game and varmints, rather than ballistic esoterica. I have sufficient bolt and lever rifles to keep me entertained with castings for a couple lifetimes. I mean no insult to those who still enjoy "The Chase", but it has gotten a bit stale for me.