Specifics of cutting a gizzy or chamber comparator gauge?

[thefitter]

If you had to describe in precise technical detail how cut a gizzy or chamber comparator gauge to a gunsmith that has never done one, how would you do it?


Thanks

 

[eww1350]

Well...this is the way I make them...
1.Using a piece of rifle barrel usually (2-3 inches) chuck it up leaving 1-1/2" + extended out of the 4 jaw chuck..indicate on the grooves to zero run-out..
2.Turn the O.D. of that portion to a cylinder about .750" diameter.
3. depending on the type of chambering (long bullets vs short)
the length of the gage should be no less than 1.250" long..to ensure a loaded round will NOT have the bullet protrude out the end..
4.Now that it is turned to a cylinder 1.25 to 1.5" inches long..use the reamer that cut the chamber using a floating reamer pusher, start cutting with the reamer until the shoulder/body juncture portion of the reamer cuts into the blank..
5.Stop the reamer as soon as the shoulder is completed..inspect the blank to ensure you have no chip galling..clean up the reamer, lubricate then push the reamer in another .075" to create a recess that the brass body can locate into..
6.Using a parting tool cut-off the gage and then finish cut both ends square and smooth..

 

[thefitter]

Thank you very much!

 

[lynn]

Fitter
If the gunsmith has never made a barrel stub or Gizzy pick a different gunsmith for your project.After the first 20 shots the only use for one is remembering what your old seating depth was when the barrel was new.
I have a bucket of them and they never get used.
Lynn

 

[justme]

I assumed they could also be used to set up a resizing die ?
I say assumed because I don't know. Any info appreciated.

 

[Cheechako]

Lynn

I believe you are thinking of a Gizmo, the little tool that is used to measure throat erosion. Like an old man in a whore-house, they are only good one time. The Gizzy measures shoulder to base and is used to determine how much (or little) to bump, as "justme" suggested. There is also the Gizma which measures bullet seating depth from the case base.

Or, maybe I have the names backwards? :

Either way, you are right about one thing. If the gunsmith doesn't know how to make one, he's not a Benchrest Gunsmith and it's time to find someone else.

Ray

 

[lynn]

Cheechako
Its no big suprise that I do things differently than most.
On my dies if they are to be removed from the press I paint a stripe on them the same color as the press they are being used in.Green for RCBS orange for Hornady red for Lee Classic black for Pacific and black and silver for Corbin.
Once that is done the Gizzy/Gizmo/Gizma/Barrel stub is obsolete as I simply line up the stripe.
Lynn