The early Chinese commercial SKS's were pretty bad - Alan Lever used to warn people that the SKS "D" was not the equal to commercially produced rifles from anywhere else. I take it the rifle shoots just fine - most of them did. The warped receiver and out of time barrel doesn't surprise me on that rifle, they were the first rifles that the Chinese made for the US market and the QC was almost non-existant. Most of the owners never realize that those issues are there, because the gun always goes bang and hits the target at 100m. If, however, you apply a straight edge and try to verify that the receiver is true you will run into more than a few that aren't. They were built down to a price point, as long as they worked, they shipped. The Mil versions are very different indeed.