TO all,

Had a customer come into the shop this morning and we were talking over the details on a rifle he wants built and he asked me a question tht I really did not have a solid answer for, here it is:

"Can you use a 30-06 Ack Imp set of Headspace Gauges to measure the headspace on a standard 30-06 chamber?"

I told him I would find out and tell him. I have used standard brass inthe '06 family when chambering AI chambers but have never used or heard of using the AI headspace gauges to measure the standard chamber.

Any thoughs on the matter would be great!

Good Shooting!!!

50

I wouldn't. A properly headspaced AI should result in a crush fit for a standard round.

Like ramrod340 says,the AI's are a crush fit in the standard chamber.You use an AI go-gauge and a standard gauge for no-go.Thats the way Mr. Ackley set it up.To rechamber a standard to an AI you must set the barrel back to acheive this.

Are not most "AI"s wider at the shoulder than the standard rounds? Do the guages reflect this?

I don't know, but would like to know.

Bob

B Stephenson asked,
Are not most "AI"s wider at the shoulder than the standard rounds? Do the guages reflect this?

No, the gauges are not wider. The only dimension that matters is for the breech face to the point on the shoulder used as the datum line.

Using AI gauges in a standard chamber wouldn't tell you anything of value. A GO gauge for a standard chamber is often used as a No-GO in an AI chamber. You could expect a standard chamber to close on both a GO and NO-GO AI gauge.

Thanks Mark

If the head space is different with a AI gauge and chamber how does one safely shoot std rounds in improved chambers?

Zimhunter,

The Ackley rounds are generally chambered so that when you chamber a standard parent round, the shoulder is crushed between 0.004" and 0.005".

Personally, when I chamber Ackley Improved rounds, I use the brand of brass that the customer want to use, in fact I will ask him to supply some pieces. Then I will use those cases for headspace gauges and chamber the barrel so that the Headspace is set at -0.004-0.005". THis will allow for the exact crush fit for that brand of brass.

I have also found that often virgin brass is several thousands shorter to teh dantum line so I feel I get a more accurate crush fit using a specified brand of brass to set the headspace.

Other brass can add or subtract a couple thousands to the damtum line but they have always worked fine for my customers and my rifles.

Thanks for the information, this is what I was thinking but did not want to give an answer until I got a group concenses.

Thanks!

50