How do i measure free bore in my gun ?

[wzee]

How do I measure free bore in my gun ? new at this !

 

[Dusty Stevens]

Youll have to ask the gunsmith

 

[Scott Harris]

What are you trying to do? Usually, people don't need to know the absolute FB number on a chambered barrel. Rather they need to know whether the FB is correct for the chosen bullet. Use the Hornady Overall Length(OAL) Gauge to do this. Have you tried this?

 

[johara1]

put your reamer on a optical comparator and compare it to what is written on the print ……… jim

 

[lpreddick]

Will this work? Use a Sinclair chamber length space gauge to determine the chamber length. Insert a flat base bullet in a prepped case(as light neck tension as possible to hold bullet but allow it to seat deeper with minimal force). Chamber this case and when the bullet's base touches the very beginning of the lands, it gets pushed into the case neck. Measure this case/bullet's length. Subtract chamber length from this measurement and you will have the freebore. May not be to the .001, but close.

 

[XTR]

Will this work? Use a Sinclair chamber length space gauge to determine the chamber length. Insert a flat base bullet in a prepped case(as light neck tension as possible to hold bullet but allow it to seat deeper with minimal force). Chamber this case and when the bullet's base touches the very beginning of the lands, it gets pushed into the case neck. Measure this case/bullet's length. Subtract chamber length from this measurement and you will have the freebore. May not be to the .001, but close.

This won't take into account leade and its relation to the angle of the ogive.

 

[johara1]

Sounds like an other guess on chamber length, Same as i posted above………. jim

 

[ELR Researcher]

Lynn suggests:

"...make a Cerrosafe cast of his chamber and measure from the lead to the start of the lands using a loupe and a steel ruler or calipers. Here is a picture of how I do it.

It will be within 0.003 and good enough for most purposes."

 

[waldo1979]

How do I measure free bore in my gun ? new at this !

Get a Sinclair seating depth tool:
http://www.sinclairintl.com/reloading-equipment/measuring-tools/bullet-seating-depth-tools/sinclair-bullet-seating-depth-tool-prod35491.aspx

If you do get a hornady coal gauge instead get the straight one. These tools are hard to use and get repeatable results. This is why I prefer the Sinclair tool.

 

[wzee]

Thanks !

 

[Brians356]

Will this work? Use a Sinclair chamber length space gauge to determine the chamber length. Insert a flat base bullet in a prepped case(as light neck tension as possible to hold bullet but allow it to seat deeper with minimal force). Chamber this case and when the bullet's base touches the very beginning of the lands, it gets pushed into the case neck. Measure this case/bullet's length. Subtract chamber length from this measurement and you will have the freebore. May not be to the .001, but close.

This won't take into account leade and its relation to the angle of the ogive.

He forgot to mention seating the bullet backwards - flat base will contact the lands, rather than the ogive.

 

[Brians356]

Will this work? ...

Yes, if you seat the bullet backwards.

 

[lpreddick]

My apology! Yes seat backwards. I shouldn't post UNTIL I finish my morning coffee.

 

[Brians356]

My apology! Yes seat backwards. I shouldn't post UNTIL I finish my morning coffee.

And I shouldn't post until I finish morning.