I'm guessing barthowes was referring to a "proper" AI "go" gauge, which is what I bought. And that is exactly what I did. Set it up so that the bolt closes on the "go" gauge and if I slip a single layer of paper behind it it would no longer close. I'm pretty sure that I followed the correct procedure. I was exceedingly reluctant to buy a "regular" 243 Win gauge, especially since all i own now is the 243AI.