Re: Colt AR15 / M16 20 round mags price check please
Nope...WAAAYYY high even in the current market from others I've seen.
Check the threads here (just today in fact) on the Thermold 20-round 6-packs with couplers for $30 (or less) per pack if you want an alternative.
As for USGI 20-rounders, I've seen numerous ones on BARFCOM and elsewhere for ~$30 or less per mag shipped (right now). Unless you just don't want to go to the trouble of tracking them down or with the trouble of getting them by mail, etc., then I'd skip $40/mag without a doubt!