Head space and the RCBS Precision Micrometer

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BadMatrix

Single-Sixer
Joined
Sep 25, 2022
Messages
124
Location
Northern Virginia
I am trying to wrap my head around Head space and if after the whole process, is this a number or setting unique to each rifle:

I have everything in order with the factory fire formed cartridges.

I have a question for correctly reading the measurements on the Precision MIC for .308.

The body has a scale with each body mark 0.050 as follows: 0.0,0.050, 0.001 and so on.

When taking a head space reading, will the headspace nut always align with the zero line on the body?
If not, if the nut stops on lets say at 5, and the scale on the body is lets say 1.5 is the measurement then 0.0065?
 

NikA

Buckeye
Joined
Nov 2, 2014
Messages
1,861
Location
Yrisarri, NM- high in the Manzanos
I don't own this tool, but I did read the instructions to attempt to answer your question, since I have a fair amount of experience using micrometers.

I would say that of the headspace nut is far off the zero mark, you've either got the incorrect model or something is far off about either your firearm or measuring method. Based on the instructions and the limits of typical headspace, your measurement should be within 10 markings on the nut of the zero mark (0.010").

Each full revolution of the nut is 0.050" based on the product pictures I see online. If the body stops at 1.5 and the nut is aligned at 5, the measurement would be 0.155".

Hope this helps.
 

BadMatrix

Single-Sixer
Joined
Sep 25, 2022
Messages
124
Location
Northern Virginia
I don't own this tool, but I did read the instructions to attempt to answer your question, since I have a fair amount of experience using micrometers.

I would say that of the headspace nut is far off the zero mark, you've either got the incorrect model or something is far off about either your firearm or measuring method. Based on the instructions and the limits of typical headspace, your measurement should be within 10 markings on the nut of the zero mark (0.010").

Each full revolution of the nut is 0.050" based on the product pictures I see online. If the body stops at 1.5 and the nut is aligned at 5, the measurement would be 0.155".

Hope this helps.
thank you....
IMG_0842.jpeg
 
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