I dunno, I haven't been able to find any since the last presidential election. Cheaper Than Dirt has some at prices about 10 X the normal price, and there are a few individuals on various BBs selling them at inflated prices, but other than that, they've disappeared.
I've got a Sig Mosquito and a M&P 15-22 that will cycle nothing else, making them useless without CCI Mini Mags.