Bullet profile checker

[Al Nyhus]

I was making some bullets last week and checking the base-to-ogive dimension in my usual way. I know that some people are more concerned about the actual ogive profile when it comes to seating depth checking, so I made this little tool to check the profile of my bullets with.

#1 Just a piece of scrap Delrin I had laying around. I turned a stub on the end that fits tightly in a Stoney Point Comparator body.

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#2 Then I put a .125 hole all the way through it.

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#3 Here's how it fits on the Stoney Point Comparator Body.

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#4 I took a small boring bar and made a .312 dia. hole in the large end about .600 deep. Then, I mixed up some epoxy, filled the hole with it, waxed one of my bullets, and pushed it into the hole. The .125 through hole allowed the excess epoxy to escape. I let it dry for 24 hrs., popped the bullet out, redrilled the .125 hole and ran the .312 boring tool into the piece just far enough to give some clearance around the majority of the shank length. What I ended up with was a perfect impression of the ogive profile of my bullet. I underexposed this pic to give a better idea....sorry for the fuzzy image....hadn't had my second cup of Sulawesi yet that morning. The .125 hole opens up the nose portion so the metplat of the bullet doesn't influence the measurement.

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#5 Attach it to the dial caliper and zero it.

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#6 Now you can insert a bullet and measure the dimension to the base. Any measurement changes have to be in the ogive profile.

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Having some time on my hands this week, I sorted 1,000 of my 117's using this method and compared it to the base-to-ogive method. I also intentionally made some bullets with differing base-to-ogive dimensions and compared those dimensions to the results when measuring from the profile to the base with this little gizmo.

For what it's worth. -Al

 

[Butch Lambert]

Al,
I think a tool made like that would be more valuable checking loaded rounds. Who cares if one is a little different from base to ogive?
Not throwing rocks at you as it is a very neat tool.
Butch

 

[Al Nyhus]

Al,
I think a tool made like that would be more valuable checking loaded rounds. Who cares if one is a little different from base to ogive?
Not throwing rocks at you as it is a very neat tool.
Butch

I agree, Butch. -Al

 

[mikecr]

No, this doesn't check ogive radius(profile). your reinventing any bearing surface comparator.

To check Ogives means measuring from one point on the nose to another -on the nose. Such a check is done with what amounts to 2 different cal seater plugs(with the smaller cal sliding inside the larger). With a distance measured between these points, and the nose type known(tangent/secant), you can calculate ogive radius. If the 'type' falls under 'other' or multi-radius, you can still compare variance in unknown radius.

You can buy such a tool or make one with a Buhay-Tubbs base/custom seater plug/and dial indicator.

 

[Butch Lambert]

Thanks for your valuable knowledge, Mike! I have a file for your post.
Butch