[smokingfrog]

Magpuls are probably the best thermoplastic magazines.

If you want metal magazines, the Brownell magazines with the Magpul follower are also very good.

http://www.brownells.com/magazines/rifle-magazines/magazines/ar-15-m16-30rd-223-5-56-magazine-with-magpul-follower-prod24307.aspx?avs|Action%20Type_1=Semi-Auto&avs|Cartridge_1=AKK_5xzzx56%20mm%20NATO

[PROCON]

I just today went and bought a couple of .223 Magpul mags from Cabelas, $13.00 apiece; just loaded them as a matter of fact...