SVT40 has been known to dislike Chinese corrosive surplus.
It is also the only milsurp rifle I've heard of that has trouble with being able to consistently fire a certain type of military surplus ammo....
I'm not so sure about that. I'd been firing Chinese surplus out of mine with no problems at all. No feeding, ejecting, or primer strike issues. 100% *bang* every time. Went through half a crate of it and was getting good accuracy out to 200yards - the trajectory was matching the adjustment on the sights perfectly. Zeroed at 100 yards, moved out to 200 yards and one click on the rear sight and it was still bang on - no trouble picking off an IPSC target at 200, 5/5 on paper if I was doing my part, and 2/5 in the A box.
Was out yesterday with some of the Bulgarian silvertip and it was a different story. Reliability was there, no *bang* problems, but I was hitting 5-6" high at 100 yards. Zeroed it at 100 (always take my sight adjustment tool with me), and then moved out to 200, clicked up the rear sight, and it was going 5-6" high again. At 300, I clicked up the rear sight for the range, and I was sailing a good 12-16" high.
For my SVT, I'm going to stick to the Chinese. The trajectory indicates it follows the ballistics of the sight way better, which indicates it's a closer match to the original design spec. That doesn't mean that the Bulgarian silvertip is bad, just that it's a bit hotter than the rifle was designed for.
Both are fine out to 100 yards for group sizes, pretty decent accuracy and all. It's once I start heading out to the 2-300 yard lines that the Bulgarian is giving me grief trying to figure out elevation and holdover.
The Chinese I got off TradEx - 1971 production. The Bulgarian I got off WSS, and was also (I didn't notice until I got home) 1971 production.
And it isn't a case of "Your Mileage May Vary" but that "Your Mileage
WILL vary." These are old guns firing old ammo. There are so many variables at play. It's going to take some experimentation to figure out which ammo your rifle likes.
Mine likes the Chinese and the MFS hunting loads, but doesn't seem to be a fan of the Bulgarian. But that's Ok, because my Tula M44 likes the Bulgarian just fine, and I only shoot that one out to 100 yards so I'm a lot less concerned about trajectory and holdover at longer distances with it.