.223*PMC X-Tac 223/5.56 - 62gr FMJ-Green Tip - 500 rds*A223PMCX
I recommend PMC X-TAC .223
500 round case for $147 is a damn good deal for these rounds. I put almost 1000 rounds of PMC through my AR without any malfunctions. I would stay away from steel case .223s such wolf, brown bear or tul.
As for the 40S&W, a good and cheap ammo for plinking you should definitely go with Blazer. They are non-reloadable but they are good for target shooting and shoots really clean.