Where can I find Beretta M9A1 High Capacity Mags?

I know the law. But finding pre-ban magazines is difficult. During the old federal AWB no one could make new magazines for the civilian market. But it had an odd after effect. Many companies stopped making them over 10 rounds for even the military. To them it was not cost effective. During the ban a lot of the military M9 mags were only 10 rounders. What ones were not were failing regularly. And to offset it the military started buying civilian supplies. So very few pre-ban mags exist for that specific gun.