When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
in that case go with a softpoint. mushrooms nice but good weight retention. a varmint bullet might break up before hitting vitals and an FMJ will sail through without using all it's energy.
You could buy a .22LR conversion with a few mags for the AR and over 5k rounds of .22 for the price of 1k of cheap .223, especially if all you're using it for is plinking.