I used to handload 125 and 130 gr. pointed sp's to 2450-2500 fps in my old Savage 340 bolt action .30-30. I eventually quit using them on deer and went back to 150 and 170 grain bullets because the lighter ones didn't give me the through and through penetration I wanted on a consistent basis. Yet somehow, miraculously, 125 grain sp bullets going 100 fps or so slower out of the 7.62x39 will penetrate like the dickens. My fuggin' azz.
Sounds like you have a personal problem with your azz; either fuggin' it, or talking out of it.
As for the 7.62x39, I've yet to have one of those bullets not fully penetrate and exit the deer I've shot with that round. The blood trails, on the three that have actually moved from where they were shot, were excellent.
Oh, and those bullets you loaded were not the same in design as the ones in the x39; neither in construction or in velocity performance window. There'd be a few hints there, but I doubt you'll figure them out.