Sinclair 22 caliber chamber length gauge

[71GTO]

After waiting for quite a while for my Sinclair chamber length gauge to be delivered it finally arrived today. I followed the instructions to a tee and repeated the measurements 6- times. Evidently this gauge is accurate or at least very consistent because all 6 of the measurements were within .001" of each other. So the chamber length of my Savage Axis II .223 is 1.785". Because my chamber is much longer that the SAAMI 223 length of 1.760" what length would be safe for me to trim at? Hopefully I asked that question correctly, but just incase I didn't, I'm basically asking what is the longest that I should let a case grow before needing to trim? Is it say .010" under the 1.785" chamber length? Also so I don't have to bother you fine people with another question later, what is the shortest length case that you think would be safe in this chamber?
Thanks again for all your help and support and please stay safe, Tom

 

[horsey300]

After waiting for quite a while for my Sinclair chamber length gauge to be delivered it finally arrived today. I followed the instructions to a tee and repeated the measurements 6- times. Evidently this gauge is accurate or at least very consistent because all 6 of the measurements were within .001" of each other. So the chamber length of my Savage Axis II .223 is 1.785". Because my chamber is much longer that the SAAMI 223 length of 1.760" what length would be safe for me to trim at? Hopefully I asked that question correctly, but just incase I didn't, I'm basically asking what is the longest that I should let a case grow before needing to trim? Is it say .010" under the 1.785" chamber length? Also so I don't have to bother you fine people with another question later, what is the shortest length case that you think would be safe in this chamber?
Thanks again for all your help and support and please stay safe, Tom

Manuals do list the trim to length.......if you change trim length, I'd plan on measuring for coal too.... And it's not gonna stretch from saami to your measurements in one firing, so adjusting coal likely more than once. Potentially this might mean needing more than one load workup.... I trim every time I fl size and fl size once every 4-5 neck sizings (non semiautomatic rifles).

 

[71GTO]

Is there any other advantages of keeping the case length closer to the chamber length other than not having to trim as often?

 

[Demi-human]

A very close fit to the end of the chamber can prevent carbon from collecting in the small eddy created by the gap between it and the end of the brass. The carbon ring deposited here can build up and begin to squish and scratch bullets as they pass by, and also make chambering difficult.

However, cases that are too long can be pinched around the bullet as they are compressed together through the throat upon firing, raising pressure. So too close isn’t good. The shoulder will stop the case, the neck won’t if it’s too long.

I find strict sizing to be more beneficial to having to trim less.
In fact, as I do trim my target cases very close to the end of the chamber, I trim my brass every time I process it.

 

[243winxb]

Because my chamber is much longer that the SAAMI 223 length of 1.760"

The 1.760" is maximum case trim length. Not chamber.

The SAAMI chamber drawing has a chamber length of 1.772" + .015" * The diameter is .254" If i understand it correctly?

So, what diameter is the Sinclair tool.
Correction *

 

[243winxb]

what is the shortest length case that you think would be safe in this chamber?

SAAMI is 1.730" as the shortest.

I'm basically asking what is the longest that I should let a case grow before needing to trim? Is it say .010" under the 1.785" chamber length?

Trim when brass gets to 1.775" , if your feeling lucky.

Or follow the book and use the "Safety Zone" maximum trim length of 1.760"