Pick some blue box Federal .308, it is decent ammo and lower end of the cost scale. If the federal works in the gun, then you likely have your answer.
Although, I run steel case in my AR with no problems whatsoever.
I have a Rem. model 740, the model 4's great grandfather, and the one time I tried shooting mil surp ammo in it, it misbehaved. But my 740 has run any brand of sporting ammo I have ever fed it.