More good information. I already knew two of the methods. I agree using a micrometer is best. But, I wasn’t aware of the neck bushing method. That is a great idea. Thanks.
For a non-custom chamber, would you say that measuring the OD of a fired neck is close enough to get the chamber neck dimension or would doing a chamber casting with cero-safe be better?
With my level of experience, a chamber cast would be better. When fired the OD of the case neck expands to the chamber walls, releasing the bullet. It then contracts milliseconds later allowing you to extract the case. I do not know a way of analyzing how much the case contracted = making the OD an inaccurate way of knowing the neck chamber dimensions. Asking this question to a gunsmith might give you more information. Thanks for the question.
So is the chamber neck size from saami specs or is it actually measured for each chamber? I understand the brass(neck and shoulder) is fire-formed to the chamber with slight rebound (as it cools?) which allows good sealing of gasses then extraction.
Thanks for the comment. To answer your question - both. On my custom rifles, the gunsmith gave me the measurement from which he measured. On my factory rifles, I use Saami. On the second part - the whole case expands to the chamber dimensions then contracts. However there is another piece of the puzzle and that is work hardening of the brass. That leads to the discussion on annealing. Hope this helps.
I appreciate your clear explanation and reasoning of why and how to measure neck clearance. Thanks for your videos!
You are welcome. I very much appreciate your kind words. I hope I am able to give you another tool to put in your existing tool box.
More good information. I already knew two of the methods. I agree using a micrometer is best. But, I wasn’t aware of the neck bushing method. That is a great idea. Thanks.
Glad I could add to your "pool of knowledge"
For a non-custom chamber, would you say that measuring the OD of a fired neck is close enough to get the chamber neck dimension or would doing a chamber casting with cero-safe be better?
With my level of experience, a chamber cast would be better. When fired the OD of the case neck expands to the chamber walls, releasing the bullet. It then contracts milliseconds later allowing you to extract the case. I do not know a way of analyzing how much the case contracted = making the OD an inaccurate way of knowing the neck chamber dimensions. Asking this question to a gunsmith might give you more information. Thanks for the question.
So is the chamber neck size from saami specs or is it actually measured for each chamber? I understand the brass(neck and shoulder) is fire-formed to the chamber with slight rebound (as it cools?) which allows good sealing of gasses then extraction.
Thanks for the comment. To answer your question - both. On my custom rifles, the gunsmith gave me the measurement from which he measured. On my factory rifles, I use Saami.
On the second part - the whole case expands to the chamber dimensions then contracts. However there is another piece of the puzzle and that is work hardening of the brass. That leads to the discussion on annealing. Hope this helps.