I've done some reloading for x39 using PRVI Brass from commercial loads. I load them for my CZ, not for my SKS. THe SKS rips the crap out of good brass and is difficult to find them. In all honesty, I find its not worth the hassle to reload them considering the PRVI loads shoot 4 out of 5 rounds in a dime at 100 yards. Thats getting difficult to top, not impossible, but just not worth the hassle.
Another consideration for trying to reload x39 was to up the bullet weight to 170gr to match a 30-30 load. This worked ok, but the re-sighting of the heavy load gave up the ability to shoot cheap loads for sh*ts n giggles, so I went back to sighting for factory/surplus loads.
At the end of the day, I picked up 40 boxes of PRVI soft points for hunting and still have most of them. I enjoyed playing around with the loading and test firing as that is what the hobby is all about. Still, I can't make a load shoot any better than the PRVI commercial soft points, and I wouldn't save a great deal of cash doing so. My time was better spent on other things.