That mag is legal AFA the feds. Despite what MikeMade said, there is no such law, never has been. The only federal law that dealt with magazines, was the assualt weapon ban,which ran from 1994 to 2004,and which attempted to ban the manufacture and sale of NEW magazines of more than ten round capacity. Any magazine manufactured or sold in the USA during that ten year period of the laws existence, was required to have stamped on it "For law enforcement use only"
In late 2004, the BATFE issued an open letter regarding hI cap magazines, basically stating that the old rules, that is, no rules applied and the ownership and possession of "LEO only mags" by civilians was now allowed.
I was trying to get a link to that letter, but it seems the BATFE website is now down.
Note that while the Feds have no such retrictions, some states do, I BELIEVE Cali, Mass, Ill, NY NJ ban more than ten rounders, and maryland I believe bans mags over 20 rounds. These local exclusions have nothing to do with the Federal law, and are groundless anywhere else.
MikeMade needs to be more aware of what the laws really are, not what he gets told by the errornet. For what it's worth, I have a couple of Beta C mags, one for my HK and one for my AR.
www.betaco.com
one hundred round mags are fun.