Chamber Length Gauge

[Butte Sink]

I purchased a Sinclair Chamber Length Gauge for my 300RUM

I'm kind of anneal regarding consistency and trim my cases each reloading session typically finding the shortest case and then matching all to it, typically in the end they will come out at 2.823, well below Saami Max / Min specs 2.850 - .020

So for grims, I purchased a gauge just to see exactly where my chamber is at, checked 5x and it's a on deep side at-- 2.887 meaning I could have a trim length at 2.867.

I'm thinking I may want to let those cases stretch a little?

 

[SKWERLZ]

The neck length gauge correct?
Yea I always minimal trim to keep them barely squared and let the lengthen out a bit to get closer to max.

Does it help?
Don’t know but it makes me feel good.

 

[Butte Sink]

Yes its a 2.887 with the gauge.
My thoughts exactly, peace of mind

I have roughly 525 rounds through it, could it be throat erosion?

It's a custom build, I guess I could contact the maker and see if he has the reamer specs

 

[Coyotefurharvester]

Minimum chamber length spec is 2.8600 just going off Saami, and your measuring,set your trimmer at 2.850.

 

[PhilC]

So for grims, I purchased a gauge just to see exactly where my chamber is at, checked 5x and it's a on deep side at-- 2.887 meaning I could have a trim length at 2.867.

Correct.

 

[243winxb]

I maintain the maximum trim length. Checked at every loading. A thousand or 2 over, not a problem.

Most chambers are longer then the maximum trim length. I call this area the "Safety Zone"

The SZ keeps a loaded round from getting crimped into the chamber on loading, if for some reason, the brass missed trimming.

 

[Eraser]

I maintain the maximum trim length. Checked at every loading. A thousand or 2 over, not a problem.

I agree. Why trim off valuable neck length.
I measure the chamber length and trim to .010 of the maximum.

 

[NorCalMikie]

And keep in mind, "most chambers" are cut about .020 longer that Max trim length.
SO, know your "actual measured chamber length" and only trim when needed.