What guages would you use to head space a 243AI. 40 deg. sholder, would standard 243 Win. guages work.
Dave

243 AI guages...

Remember you gotta chamber a Ackley (non belted case, the belted are easier) at least .004" shorter than a standard chamber so the case will be held tight in the chamber for fire forming. And, I usually chamber the varmint and target rifles tight anyway, so the bolt will not close on a go gauge. Not so with a hunting rifle, especially a DGR, as you want any and all ammo to fit the chamber. So, with an Ackley, get at least 100 new cases from the same lot, then sort for size ( I use a special gauge and a dial indicator that measures headspace)and use the shortest case as a "gauge". You want the bolt to be snug on the shortest case. Now, another thing to be aware of is case length varies from manufacturer to manufacuturer, and from lot to lot for a single manufacuturer, and even varies in the same lot!!! So, you gotta measure before chambering. And, I have a special Ackley gauge made by my reamer maker whenever I have an Ackley chamber reamer ground. You can get by without a gauge, takes a bit of careful measurement, but the proper gauges makes things easier, especially if you do as I and chamber a lot of barrels.