The tapco original ak stock insert does not properly press against the rear trunnion like the saiga factory stock or the kvar does because its too short. If I am not mistaken, the 74 style trunnion has a deeper trunnion step than the older AKM pattern. This is obviously the case with the 100 series AK101,102,103,104, etc. This would mean the 1mm receiver edge would bear the full recoil impulse upon firing instead of the lower trunnion step as the design intended. A simple fix would be to use a spacer 4 or 5 mm long. Unfortunately Tapco overlooked this difference and leaves it to the buyer to deal with it. So if you want to use this tapco stock it should fit a wasr, SAR, Maadi, hungarian AKM build, bulgarian AKM build, Romanian AKM build, Russian AKM build, or any other AKM type build. It just does not fit the Ak74 or newer derivitives without some modification like a spacer. For a visual comparison, a took a picture of the tapco original ak stock right up against a saiga factory stock. Notice how the tapco insert edge is several mm shorter than the factory one. This leaves the outer stock lip to bear the main contact support against the receiver edge marked in blue when the insert edge does not.