But you may not have known that there are different standards for true dimensions, which is why I have to shave ¼” off my 6x6 post (really 5¾”) so that it fits into my 6x6 bracket (really 5½”).
That’s because I bought 6x6 “rough sawn”, but my brackets are designed for 6x6 “construction lumber”. Both are named “6x6”, neither is actually 6” square, each has different true dimensions.