I have recently purchased the 4 position gas block for my saiga-12. I am having extracting and ejecting issues with ALL types of ammo. The strange thing about some of these failures is the bolt will shut on a spent round that has been ejected just a small amount. The shell gets "pinched" inside the chamber. I have tried every setting on the new gas plug, tried all types of ammo and the 12 round "stick" mag as well as my 20 round drum. If anyone has had similar issues or know something else I can try please let me know.