Chamber length

R

Redcrow

Guest
I set up my Sinclair chamber length gage insert today and took a reading. I was very suprised at what I found. .023 difference?? Can this be? I expected some difference but not really this much.

Rifle: Savage .308 F T/R, factory barrel, about 500 rounds through the barrel.

2.015 maximum case length (found in numerous published articles & books)
2.038 my measured length using the Sinclair chamber length gage

.023 difference

Wow, given that chamber length I doubt if I ever have to trim again.

Opinions please...........
 
I agree with Bryce. Nothing unusual about that.

Mike Swartz
 
the saami drawing for the chamber is 2.025 at 0.3442 dia, there is a step that drops to 310 dia and 2.0488 lenght.....

what is the dia of your tool and the length tolerance is plus .015.....

all adds up to you are not that bad...for a factory gun...and yes now you know what to trim your bass to.

mike in co
 
mike in co said:
the saami drawing for the chamber is 2.025 at 0.3442 dia, there is a step that drops to 310 dia and 2.0488 lenght.....

what is the dia of your tool and the length tolerance is plus .015.....

all adds up to you are not that bad...for a factory gun...and yes now you know what to trim your bass to.

mike in co
Click to expand...

Just checked it, .3340
 
Chamber lengths

Redcrow: I also use the Sinclair chamber length gages, and also have many chambers that are as much as .038" longer than maximum case length. If I paid attention to "advice" and trimmed-off to .010" shorter than maximum case length, I could have as much as a 3/16" gap in front of the case mouth: like shooting 22 shorts in a long rifle chamber. This is the area ( in front of the case mouth) where a ring of carbon will build up. It's an on-going problem with closely fitted cases (6ppc, 6br, 22br) that do not stretch and never need trimming. Next chambering reamer I buy, I'll specify the overall chamber length.:(
 
Chamber lengths, again

Sometimes the finger works faster than the brain: measurement above should be 3/64", ( the gap in front of the case mouth), not the 3/16" shown.
 
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