Sierra lists IMR-3031* (Hornady also) /IMR-4895/IMR-4064 (Hornady Also) /IMR-4320* (Hornday also) /IMR-4350 ((Hornday also) /IMR-4831
Hornady Lists: H4895/ Accurate 4350/ VIHT N-160
R-17 oddly is not listed in Horndy that does have it in 30-06. I have found 30-06 high loads too hot for the 7.5, so starting low and working up is needed (more efficient?) it is a shorter fater case.
In the 7.5 Savage 110 I built I was getting hard bolt lift in R17 at 52 gr.
I have taken down GP-11, powder in it is a like 48.9 and identical to R-17 as noted.
K-31 does not have the cam action a bolt does so not one I would push.
I have notes of H 4350 in the K-31 of 47 gr.
I have not gotten much out of the K-31 that satisfies me, the H4350 did work but has gone off.
In the 7.5 Savage 4831 has worked at times, H4350 and working with IMR-4350 (easier to get) now.
As the case capacity is virtually identical to 30-06, any 06 powder would be worth a try, starting low of course and working up and be aware mid high is the limit.
30-06 lists R-17 up to 59.2 and that is clearly way to hot for a K-31 (and the Savage)
Nothing bullet wise like a GP-11 bullet, its just strange (no straight to the side at all, curves from tip to the change point and a long boat tail after.
My K-31 is in great shape but I have yet to get it to shoot consistently. I do have the Scope mount for it (non intrusive ) and it works well. I can't see iron sight that well these days.
I have found it a most interesting caliber, pretty much a RUM well before RUMs came to be. Highly advance case and a bullet no one has duplicated in the GP-11.
Its a shame is so niche, it would give the 06 a run for its money.