Bearing Surface Length Measurement Question

[royinidaho]

I rigged up the following gizmo which as passed all of my tests for usefulness and consistency of measurement.

My question is what should the diameter of the hole be to provide data that is consistent when shared with others. Info to be shared would be Base to Ogive, bearing surface length.

I guess that there must be a pretty much standard ogive diameter??? I read somewhere to make the hole 0.011" under the cal. diameter. Not sure if that's a good number.

Cals I'm interested in are 222, 277, 338.

Any help would be appreciated. Thanks

[jmden]

Roy,

Nice work but why not use a gizmo like a Sinclair Bullet Comparator?

http://www.sinclairintl.com/cgi-bin/...amp;type=store

[royinidaho]

Where in the heck have I been [img]/ubbthreads/images/graemlins/blush.gif[/img]

Its ordered.......

Thanks

[davewilson]

most comparators use something close to the bore dia of the caliber. a 308 would be .300... a 270 would be .270. i think a 224 would be .218, not sure about that one. a 338 would be .330.

[royinidaho]

Dave, If I had half a brain I would have known that! Duh!

Nevertheless the Sinclair thinger is on the way.

When are we gonna get further info on your project......

[goodgrouper]

The Stoney point method works just as well and is cheaper. You could possibly even make a way to hook the inserts up to your contraption if you got inventive enough.

[royinidaho]

Grouper, I'm getting tired of all of this innovativeness [img]/ubbthreads/images/graemlins/blush.gif[/img] I've had that bad habit so long I have no idea of where I got it.....

The sinclair thinger will go under the dial indicator. I'll just have to set it up an inch or so higher on the rod.

+ Santa's gonna bring me a digital caliper. I can never find my magnifying glass for the one I've had for 30 years. [img]/ubbthreads/images/graemlins/frown.gif[/img] [img]/ubbthreads/images/graemlins/frown.gif[/img]