I bought a pair of these mags for use in my CYMA CM.046 AK.
+ Good external quality: These mags are quite a bit longer than the standard 30 round AK magazine and are just as rigid. No loose baseplates or top pins that fall out easy, at least out of the box. They fit into the gun well with about as much play as a standard CYMA AK magazine.
+ Capacity: These mags were originally for the RPK 47, a support gun, but they can be easily used in a regular AK. While vertically longer than the standard AK mag by around 2 inches, you do get an extra 200 rounds at your disposal.
- Typical super-high cap issues: The two I purchased functioned great for the initial 2-3 game days I used them in, but things started to go downhill from there. One has a problem in which the clip that holds the winding wheel continuously falls off; the other doesn't seem to feed consistently anymore, requiring constant winding even when the spring coil is already wound tight.
Verdict: If I was in the market for an extended magazine for the AK, I would consider alternatives, though the issues I mentioned above are fixable. The Dboys 1000 round coffin mag looks pretty interesting, though honestly, I think I'm just going to stick with my 3 CYMA standard 600 rounders for a while.
Sorry that you had some issues with these. If you're in the market for AK47 mags, check out the DBOYS AK47 1000RD AEG MAGAZINE!