for plinkin with the semi's I just buy cheap ammo but not too cheap you dont want to shoot that gunky russian stuff in an AR-15 the gas system just wont take it and eventually you will be replacing the gas system in it. I go for PMC or PMP you can get a box of 20 for around 4 bucks which is about the same cost as reloading them. I do reload .223 though but not for plinking thats what the stuff I buy in bulk is for I do however put a little time into my 223 loads and worked them up for accuracy.