got a quick question that I hope I am right on.

I ordered a RCBS Precision MIC to measure the brass for reloading and my brass was larger than the Dimensions according to ANSI (American National Standards Institute) According to ANSI the brass Dimensions from Base to the datum point on the shoulder should be 2.1253 to 2.1353 inches. After FL resizing my brass even to the smallest possible size its still long. I measured factory ammo and it was under ANSI by 15 thousands of am inch. I just want see if anyone else has come across this and if there is anything I need to worry about.