Where can I find 20 new factory Colt magazines? I need them to either have the new tan bodies and blue followers or the last gen. that had the tan followers.

You're gonna have a hard time with that.  

Center Industries has the contract for the new tan w/blue follower.  

There are reports of tan follower Colt mags, but I haven't seen any personally.   Center, Brownells, and a few Okays are the tan followers I've seen.

Thank you for the response. After researching, it looks like BCM is going to have the closest match and be most reliable for aluminum magazines. The Gen3 Pmags are the "USGI" mags for the Marine Corp and Army now.

Okay's are the best usgi aluminum mags made IMHO.  Iirc they made/make the Colt branded mags as well as the nhtmg mags when they were around. Okay mags are all I buy anymore.

BCM's magazines are made by D&H with BCM baseplates to "brand" them. D&H does that for a lot of different companies, like Palmetto State Armory and, I just discovered, Noveske. I know a lot of people like D&H, but I haven't been impressed with their construction, putting them next to a true GI magazine like Okay or Colt. They seem a little bit thinner (or made of lighter aluminum), and the spine and other seams seem a bit sloppy to me.

The Army hasn't adopted PMAGs yet, although it's possible to order them through the Class IX system using the NSN printed on the magazine. The standard Army magazine is the brown Enhanced Performance Magazine (EPM) right now.

I like Okays and Centers for g.i. mags.   The Brownells are probably just as good, but I just don't like 'em for some reason.

D&H is the old Labelle brand which was a USGI supplier. Interesting that you've had issues. But they could have changed their manufacturing process since they're no longer a contractor.

Just FYI you don't need fancy followers in the straight 20 round mags.

The lack of curvature negates the need for a "no tilt" follower.

They don't even work with anti-tilt followers.  It'll bind up around 15-16 rounds.  

The case has a taper, the mag body has to curve, or the follower has to tilt.

This mag design is pretty much perfected. I have many different types. All are reliable. I even use real Nam era 20s and have yet to see an issue.