How do you measure crimp?

This is kind of a spin off of the load optimization thread, but I never felt all that confident in measuring crimp. 

Round micrometer anvils rolling over the end of a tapered/rolled case mouth just feels problematic, calipers even worse. 

To far down the case and that isn't a true reading, too far out and square anvils roll off the edge.

*I'd think one of those hornady oal anvil sets with one insert reamed on a taper would give consistent results, and you'd have to do some math of case length vs taper length reading to get a real crimp diameter number, and you'd need a gauge to set it against to have numbers you could swap with anyone else.  Maybe that is way off base.

What is the correct way to measure the end diameter of a cone?

Grip the case between your thumbnail and your curve of your forefinger.  Put the thumbnail just below the case mouth.  Rest your calipers on the thumbnail, make sure it’s level and then measure.  It’s as consistent as you can get without an optical comparator,

Tapered?
If you can’t see it, it’s not enough.

Calibrated eyes huh?  
Jon

Optical comparator or toolmakers microscope.

Lacking that, which 99.9% likely do ... yeah, its a pain. Setting your calipers to a 'number' and checking if they'll pass over the edge is worth a try. Start on the high side and see where they sit along the taper. Rinse (adjust) and repeat.

I measure crimp by length. Using a Dillon taper crimp die I crank it down until I see and can measure a minimum of 1/16" of taper (lead bullets)

That's about what mine look like after setting it with a microscope. Which is a pain as well. Damn things want to roll off the stage.

Easy.

I found that after doing my best to measure the crimp with a mic, that pulling a bullet and checking it is a good idea.

Wes Lorenz wrote:

Easy.

Wes - did you make that yourself? If so - can you be paid/bribed to make another one?

If you got it somewhere else - would you be prepared to share that information? I really want one - albeit with different sizing.

Made it a long time ago. Too much work on a manual Bridgeport to make.
New product for Photo Escape????

Good idea - Alex hasn't had any money from me in at least 3 weeks.

I put the case mouth down on the edge of the bench and take a reading with dial calipers.
Stan

I use calipers under a magnifying goose neck lamp.

To expand on this - I can see well enough under the glass to set the thin part of the calipers half on-half off the edge of the brass case mouth. 

Years ago LTC Miller said to crimp until you cant force the bullet down into the case by hand.  And the load was 3.4 BE

The lowest reading I can get over a few tries of measuring the edge with a dial caliper. I kind of spin the cartridge while slowly moving the jaws toward the case mouth with light pressure on the calipers.

I set the caliper to the desired crimp and lock it.  Then I see how the case mouth fits in the locked jaws.

Wes Lorenz wrote:

Easy.

Sure wish you'd posted this *before* I'd driven back to TX. Now I have to wait until January, at best.

Greetings,

Most micrometers have a spindle lock.

Set the micrometer to the desired crimp diameter.

Next, try the cartridge to see if it just starts between the anvil and spindle.

Forget the dial calipers, not precise enough.

Cheers,

Dave

fc60 wrote:Greetings,

Most micrometers have a spindle lock.

Set the micrometer to the desired crimp diameter.

Next, try the cartridge to see if it just starts between the anvil and spindle.

Forget the dial calipers, not precise enough.

Cheers,

Dave

+1 and it would be even more enhanced if you can use blade type micrometer or dissent digital caliper with tungsten jaws (Starret or Mitutoyo).  Yeah...., I know it is not cheap.

AP

PhotoEscape wrote:

fc60 wrote:Greetings,

Most micrometers have a spindle lock.

Set the micrometer to the desired crimp diameter.

Next, try the cartridge to see if it just starts between the anvil and spindle.

Forget the dial calipers, not precise enough.

Cheers,

Dave

+1 and it would be even more enhanced if you can use blade type micrometer or dissent digital caliper with tungsten jaws (Starret or Mitutoyo).  Yeah...., I know it is not cheap.

AP

If Mitutoyo Digital caliper is accurate enough, why not a mititoyo dial caliper? Is the digital mechanism actually more accurate or precise?

fc60 says dial calipers no good. PE/AP says mitutoyo digital even better. I dont think my ability to read half a thousandth is diminished with the dial ... (if the device is in fact that precise)

I just crimp until it's too much, then back off a frickey.

Boom. Problem solved.

john bickar wrote:I just crimp until it's too much, then back off a frickey.

Boom. Problem solved.

Which rather leaves the question "how much is too much"

straybrit wrote:

john bickar wrote:I just crimp until it's too much, then back off a frickey.

Boom. Problem solved.

Which rather leaves the question "how much is too much"

A frickey more than perfect, duh.

"High Master can only be made with the perfect crimp"

-said by no high master ever...

straybrit wrote:

john bickar wrote:I just crimp until it's too much, then back off a frickey.

Boom. Problem solved.

Which rather leaves the question "how much is too much"

JB's posts are very informative ........... if one knows how to interpret them.  I do not pretend to be accurate every time, but will take a stub here. John, please feel free to correct me without ripping my head off!

With that, being a human testing fixture, JB (and couple of other guys at the same level) can detect deviations of his loads from previously known quantity/quality and attribute such deviations to one or another element of building ammo (crimp, powder charge when lots change, seating depth, primers, etc.).  Subsequent "frickey" correction addresses it.  So, IMHO, is not that "perfect crimp can make one an HM", but rather opposite, - understanding of correlation between "paper work" and needed adjustments to the load.

So it is "see result and make changes" or "measure, test, make changes, measure again, test again, .....".  Needless to say, former route is more economical in all respects.

As I said, that is my interpretation.

AP