FWIW I rigged my SKS as a straight-pull bolt action (simply removed the piston assy) for use when deer hunting and accuracy using PMC soft-points was 3/4 to 1" groups @ 100-yards. No long range per this forum intent, haha, but sure was good enough for 1-minute of deer out to 200-yards!
I also recently built and AR in -39mm and used a JP Enterprises adjustable gas block and I tuned it to Golden Tiger ammo, and so far it has fed everything else I can throw through it reliably. I haven't taken a deer with any of the import soft-points less the PMC (good ammo!) but my AR really liked the Brown Bear soft-point stuff too, printing sub-MOA out to 200-yards. But of course that AR was scoped (Trijicon 1-4X, so it has GREAT glass on it) and benched and I took my sweet time.
In a way, I find import/bulk -39mm ammo to be like 22LRs, meaning one must try MANY different brands in their arm of choice to see what it likes ... not necessarily what you like. I had 8 or more brands on hand when I tested mine. Again, I tuned it to the GT just due to the amount I have on hand, but it sure liked the BB too!
I will say, the accuracy potential of bulk -39mm rounds when fired out of the superior platform like the AR (or even a bolt action) sure surprises and stuns a lot of people! I also have a left-handed mini-Mauser (Zastava bolt action) in the -39mm caliber and it shoots really well using bulk ammo. At the price I bought it for ... you cannot reload it cheaper by far ...
That bolt gun is now my dense woods deer gun using the 154-grain soft-point loads, while I use the same in the AR on really bad weather days. Let's just say, for my use in eastern woods, I like the -39mm as a deer cartridge. My Dad, for one, kiled more deer with a 30-30 than any man should be allowed to and a good loading of the -39mm equals if not bests that venerable deer cartridge. But a western-use or long-range hunting gun they are not ...
