The NoDak Spud (NDS) waffle mag (center bottom) offers a bit of retro class to any assortment of AR15 mags.
After stopping by an old friends work place the the other day, we got talking guns as usual. He is more of a hunter then I am so he was all giddy to show me two of his newer guns. After seeing them he showed me a round of each and gave me a sample to keep just for fun. I would only shoot one of them. I bet you can guess which I would not shoot! 5.56 for size
.22 squirrell , 5.56 and then 505 gibbs
the 22cal has a .22 hornet parent case