That PPU soft point is your best best for expansion, not seen any gel tests but soft point 7.62x39 seems to come in two types of bullets, the semi soft point in 123 or 154 gr. and the PPU which looks like a 30-30 bullet, much stubbier & rounded with a much shorter jacket.
You might have some feed issues with the PPU so try a box first before buying a case, it runs fine in my WASR, Draco & AK63DS. I pick it up from my local Cabelas repackaged as Herter’s.
If I remember correctly the PPU 7.62x39 stuff tagged as PSP is the semi soft point and the SP RN (soft point round nose?) is the stubby 30-30 profile.
I think Herter’s uses the same designation for their brass case 7.62x39 although it doesn’t show on their terrible website.
Also check out Geco for cheap brass case 7.62x39 fmj. Usually not hard to find for 40 cents/rnd, it’s what I stock up on when I have to shoot indoors.