Recently had 2 of the magazine springs in 5.45 mags literally disintegrate on me. One was Cproducts, one ASC.

Are the springs standard AR springs...and if so what brand would one recommend to stand up to the corrosive effects of 5.45?

Huh. I've not been shooting 7N6 for long but I've shot surplus Yugo M67 (7.62x39) thru an AR with ASC mags for years. i just recently took one of my 30 round & 10 round mags apart and the springs on both were like brand new. Are you showing any corrosion around the feed lips of the mag? Are you storing your mags with your rifle? I'm not aware of anyone making a spring that would be more corrosion resistant. But if salt is getting into your magazine bodies I'd recommend dunking them in a bucket of hot soapy water every now and then.