Just for grins, I purchased several of the "20 round green military followers" from CDNN to try in some of my 20 round magazines. I replaced the existing black plastic followers that were original to the (Colt) magazines with the green ones and headed out to the woods to make some noise. I had never had any reliability issues with the black plastic followers, but I thought I'd try the green ones anyway.
I was not impressed. I found I could only fit 19 rounds into the magazines rather than 20. Also, the last two rounds in each of the magazines (4 different magazines) I used would not consistently feed. The bolt would slide over the last two rounds without picking them up (and, yes, the springs were installed correctly).
I've never had any troubles with the "30 round" green followers in my 30 round magazines, but the "20 round" ones sold by CDNN don't work properly (at least not in my magazines). I promptly re-installed the old black plastic followers.
Anyone want to trade some aluminum followers for some "20 round" green ones?