Using a go gage to find chamber length

[cw308]

Posted on another forum , sorry , using a go gage for a 308 measurement stamped on gage is 1.630 , by adding a .002 shim my bolt closed with a slight resistance . My way of thinking my chamber from bolt face to shoulder datum is 1.632 . I have been using that measurement for sizing headspace and checking with the RCBS Precision Mic . What do you think ? I never got an answer if I was right or wrong with my system .

 

[jono]

1.630-.002=1.628....
The chamber and gauge
are what they are.

Sorry to be pedantic...

 

[stringnut]

1.630-.002=1.628....
The chamber and gauge
are what they are.

Sorry to be pedantic...

Please explain why you are subtracting instead of adding. The OP has a gauge and shim that are fixed length. 1.630+ .002 = 1.632. You are stating that if you had a block of steel 1 inch high and added a .250 piece too it it would only be .750 inches or so it seems.

 

[Blue68f100]

Do you have a NO-Go to confirm the chamber is correctly within the specified range? Do not mix mfg when using camber gauges. If your feeling a slight resistance when closing the bolt with the 0.002" shim added your are probably pretty close. Set your sizer to match the Go + 0.001" should work just fine. Would not go less than the go gauge to make it easy on the brass.

 

[Allen One1]

I think you're right. I would add a second .001-.002 shim to make sure the bolt doesn't close just to be extra safe with my assumption but it sounds like you have it figured out.

 

[cw308]

That what I do . I size my cases 1.631 - 1.630 no more or less . Just my way of checking headspace , thought it might help someone .