We sell them and stock them. They are availible now from your local dealer, no waiting lists no muss no fuss.
They are good for pliniking and when you life is not on the line.
The US military seems to agree with me.
http://www.defendamerica.mil/article.../a072803b.html
"Soldiers experienced problems from the time they were handed the empty C-MAG and ammo can full of 5.56 rounds and told to load the magazine. While loading the magazine there were numerous jams, speed loaders broke, magazines would not accept the full capacity of ammunition. "
In perfect conditions with proper lubing they work fine. drop it in the sand and pick it up or drop it from more than 3 feet and things start to go awry. Normal civilian will probably never have that much of a problem...the Military...I'll bet then never see full procurement.