A buddy of mine has a dozen AR mags, plus a couple of thousand rounds of green tips in case the omelet hits the fan. A scenario I'd have considered ridiculous a few short years ago, but nowadays nothing would surprise me.

With semi auto pistols I normally like to have 2 mags for a firearm to rotate at the range. I just got an AR and have 900 roiunds coming from Midway.
Forgot to order mags. So I have 2.

Should I go for another 5 or for 10 ? Magpulls ? With or without window ? Inquiring minds want to know.