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caliper vs micrometer

5474 Views 30 Replies 10 Participants Last post by  msredneck
I have a dial caliper that I use to measure OAL on my reloads.

Sometimes it seems that a micrometer would be handly when I want to measure bullet diameter or maybe the case mouth diameter when I 'm setting the case mouth expander die....yet the dial caliper will sorta do this as well...I guess its a matter of accuracy.

Which brings up another subject...what do you use to "calibrate" your calipers with guess a gauge block is in order here.


Guess there is no end to the "toys" a reloader must have!
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As a general rule I don't trim rifle brass...it gets pitched
msredneck said:
As a general rule I don't trim rifle brass...it gets pitched
Please save it for me!! Pitch it my way!! :cool2g:
For bigsig:

This might interest you. When we designed an automated molding machine years ago, I needed to have two curved steel beams with an "H" cross section made with a 135 inch. plus or minus 0.010" radius. The only horizontal boring mill big enough that I could find was in Wisconsin, I believe in an Allis-Chalmers plant. They declined to take contract work.

Danly Machine Co., in Cicero, Illinois made the beams, using a then-state of the art tape controlled mill which "stepped" the milling cutter in very tiny increments, a few thousandths for each move, to create the curve. The beams were 60" long, so you can see a huge block of steel was needed to start with, and a humongous amount was machined away. They stress-relieved the parts several times during the machining. When we got them, they looked beautiful! Slipped into the supports (they rode on ball bearings), they slid back and forth just perfectly!

I will try to post a pic of the molding machine taken during construction. OK if the pic has a cute chick in it??
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What is a good digital caliper without breaking the bank. I don't reload enough to pay in the 100's of $'s for a digital caliper.
SJ said:
What is a good digital caliper without breaking the bank. I don't reload enough to pay in the 100's of $'s for a digital caliper.
The $23.99 one would be considered a good one? I was assuming a good one would be much more.
Starret, Browne & sharp, Mitutoyo= top of the line
SPI, Fowler= good
value= jjjjjjjjjjjunk
Try this out

U are gonna have to drop a C-note + some change...for the "top of the line" and maybe the good stuff

My next will be a Starret...midwayisa has them for about $150

bigsig knows his tools..It's his living

The question really is...Is it really needed?...and for most the answer is No
Calipers are most defintely needed. Micrometer, not so much. Unless you are loading for 1000 yard benchrest or something like that, you probably wont need a mic. A mic is needed for checking bullet diameters to a ten-thousandth of an inch, which some benchrest shooters do. also for checking the case neck thickness, if you trim and uniform that.

For the everyday reloader, a caliper will do nicely. You must have one for checking case length, and overal length.
I use a set of "cheaper" fowler calipers to reload. All my good tools are at work. As long as your calipers read "0" with them all the way closed and there is no visible gaps in the blades you should be good.
With your calipers fully closed hold the blades toward a light and look for uneven gap. If you see more light at bottom and none at the top, then they are out of calibration.
Out of calibration...Mine are...not badly...but bad enough.
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