ACC's are the same diameter as your carbons. The tolerances on ACC's are extremely tight. They are incredibly durable, the nocks are fantastic allowing for a solid release from the string, they penetrate like gangbusters and IMHO are the best arrow on the planet.

ACC of course stands for Aluminum Carbon Composite.....

Aluminum core wrapped in carbon. Oh, they are absolutely silent in flight as well. Some other carbons make a whistle as they fly.

There is a downside however....Cost. ACC's ain't cheap, but they are worth EVERY penny.

I may take the time to post an arrow building "How to" in the technical forum this evening....