I maintain my statement if you want to use mags in an sks and don't want to mod the crap out of anything to make it work, tapco mags have never given me any trouble....and this is normally because the bolt holds open and you stripper clip into it...and voila a FULL FIVE ROUNDS at your disposal 
If you want to test, try this...you and a buddy square off full mags in the gun. You are even. Both fire five rounds in the dirt to empty them out. You are even. Each reload the same magazine and fire at each other. Not so even anymore. As I said, taking the 5 round capacity into account a gun with factory SKS mag or a tapco mag that can be loaded with stripper clips will WAY outperform any AK mag or CZ. The only proof I need is my AK magged SKS stays home and the other ones go out to play, just as the other gent stated. The upside is this keeps the collectible piece in very nice condition
If you want to test, try this...you and a buddy square off full mags in the gun. You are even. Both fire five rounds in the dirt to empty them out. You are even. Each reload the same magazine and fire at each other. Not so even anymore. As I said, taking the 5 round capacity into account a gun with factory SKS mag or a tapco mag that can be loaded with stripper clips will WAY outperform any AK mag or CZ. The only proof I need is my AK magged SKS stays home and the other ones go out to play, just as the other gent stated. The upside is this keeps the collectible piece in very nice condition