i just purchased a new dpms a15, well atleast they told me it was new!! Im concerned about the fact that it says .223/5.56 on the receiver but I cant find where it says it on the barrel. Im hoping its not a frankenrifle, and if it is I want to know if its safe to shoot 5.56? I have shot about 250 rounds through it so far, all but 20 rds. were 5.56, if it were really a .223 would I have already noticed problems? Would it be stamped on the barrel somewhere under the handgaurds where I cant see it? Im really new the ar-15 platform and i paid alot of money for this thing, I really dont want to mess it up.