.257 ai

[taxidermyguy]

Hello all! I have a question about headspacing a 257 Roberts AI barrel. Does anyone know if go no go gauges are avaliable in this caliber? i do not have a fired case since the barrel is brand new. Any advice would be appreciated greatly!

[Hotolds442]

The nice thing about AI's is that they're designed to also use factory rounds in a pinch. You can shoot 257 Roberts in the AI for fireforming. Since the AI headspace about .004 shorter than the parent case, the go gauge of the parent case is the same as the no go gauge of the AI. I have set up a 243AI before using the 308/7-08/243 (tel:308/7-08/243) go gauge and setting the bolt handle where it usually stopped on the parent case no-go gauge. That method will work in a pinch, but always check it with a proper gauge as soon as you can procure one.

Length wise, AI go gauge +.004= parent go gauge (and AI no-go).
parent go gauge + .004 = Parent no-go gauge.