Just got a flyer from J&G Sales out of Prescott, Arizona. They list Ruger 20 round factory mags for $34.99, and 5 or more are $32.99 each. J&G sells quite a variety of surplus arms and ammo. They don't show much ammo in .223/5.56mm, at present, but have a good selection of most other calibers. Their address is: www.jgsales.com. Phone # is 928-445-9650.