Ball micrometers?

Butch........

Good point.

The fixture is mainly for neck-wall thickness runout comparison.....from case to case.

The tubing mics.....yes....for neck thickness. But also compared with outside mics, measuring loaded round outside neck diameter.

But.......then there's the bullet, itself, runout......sigh....:confused:

Kevin
 
Kevin Gullette said:
Good point.

The fixture is mainly for neck-wall thickness runout comparison.....from case to case.

The tubing mics.....yes....for neck thickness. But also compared with outside mics, measuring loaded round outside neck diameter.

But.......then there's the bullet, itself, runout......sigh....:confused:

Kevin
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Kevin, We will be in WF for Judge "Barney" Fudge's retirement party on Oct 4 and our Burkburnett HS reunion on the 5th.Our class get together will be at Barney's place. I haven't been that way in years.
 
Butch........

You should have an easy time, getting through town.........

That's because, some years back, they installed two elevated "scars" across town. In their infinite wisdom......they also managed to kill many businesses below the scars.

On the plus side......the weather's been ok.:eek:

Kevin
 
Kevin Gullette said:
You should have an easy time, getting through town.........

That's because, some years back, they installed two elevated "scars" across town. In their infinite wisdom......they also managed to kill many businesses below the scars.

On the plus side......the weather's been ok.:eek:

Kevin
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Yeah I know. Kinda funny looking down at Reagan Jr. High.
 
Butch Lambert said:
Well! I'll be damned!
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For my AI varmint rifles (Panda actions with right bolt, left port), heavy stainless barrels (1 inch OD at the muzzle and 28 inches long), tight necks
I use bulk buys of commercial brass (couple thousand at a time) and then go to town sorting it out.

Trim to length.

Weight is an early one also.

One of the last sorts is by neck wall variation.

I separate it into groups with <0.0005 variation, less than 0.001 variation, any any real outliers in another group.
They are all then neck turned to 0.0100 thick.

For longer range (6 mm REM AI with low BC bullets) use I can make a group of <0.0002 variation.
600 yard groundhogs are not hard at all.
 
Why not just use ya vernier?

I have a ball mike in a stand. It sits under my loading bench. I haven't turned cases in a very long time , years, because I have so many finished cases. The solution to varying case thickness is a smaller sizing bushing. Cases are a holder for the things that really matter, exact charges of powder and bullets that are placed exactly in them, end of story.


Pete
 
Pete Wass said:
I have a ball mike in a stand. It sits under my loading bench. I haven't turned cases in a very long time , years, because I have so many finished cases. The solution to varying case thickness is a smaller sizing bushing. Cases are a holder for the things that really matter, exact charges of powder and bullets that are placed exactly in them, end of story.


Pete
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The solution is to turn them.
Keeping in mind that the variation likely extends to the body of the shell.

It makes sure the bullet is centered up in the leade.

Sizing them smaller does nothing to remove the variation that means the bullet is NOT concentric with the bore.
 
Pete Wass said:
a vernier will tell ya everything a ball mic will.

P
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Never seen a ball mike that was vernier.

Using a caliper of any type will not produce accurate
thickness measurements on a curved surface.
How wide is that flat on the jaw?

You could try to calculate the error based on the radius
of the curve and the width of the contact area.

The face of the caliper is not zero thickness.

When you are concerned with 1/10,000 variations around a small
cylinder like a case mouth ball and rod anvil are required.
 
brickeyee said:
Never seen a ball mike that was vernier.

Using a caliper of any type will not produce accurate
thickness measurements on a curved surface.
How wide is that flat on the jaw?

You could try to calculate the error based on the radius
of the curve and the width of the contact area.

The face of the caliper is not zero thickness.

When you are concerned with 1/10,000 variations around a small
cylinder like a case mouth ball and rod anvil are required.
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^^^^this.^^^^
 
Close enough for me

mwezell said:
Not even close
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with measuring rounds loaded with bullets in them, one, if they have a pumpkin turner, only needs to get close. Even if one does cases on a lathe, one is pretty much only concerned with what the o.d. of the case with a bullet in it. That's what I think anyway. With 600 finished cases, I don't turn many now a day.

I just now went in to my gun room and measured a finished case with both a Ball Mic and my Lyman vernier, they both said .009". Not even close you say? Very close I'd say.

Pete
 
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Pete Wass said:
with measuring rounds loaded with bullets in them, one, if they have a pumpkin turner, only needs to get close. Even if one does cases on a lathe, one is pretty much only concerned with what the o.d. of the case with a bullet in it. That's what I think anyway. With 600 finished cases, I don't turn many now a day.

I just now went in to my gun room and measured a finished case with both a Ball Mic and my Lyman vernier, they both said .009". Not even close you say? Very close I'd say.

Pete
Click to expand...


Chuckle chuckle chuckle
 
Pete Wass said:
with measuring rounds loaded with bullets in them, one, if they have a pumpkin turner, only needs to get close. Even if one does cases on a lathe, one is pretty much only concerned with what the o.d. of the case with a bullet in it. That's what I think anyway. With 600 finished cases, I don't turn many now a day.

I just now went in to my gun room and measured a finished case with both a Ball Mic and my Lyman vernier, they both said .009". Not even close you say? Very close I'd say.

Pete
Click to expand...

Good job!
 
For comparison I measured a neck with my Mitutoyo ball mic at .010. I then picked up my new Mitutoyo Digimatic calipers. I found if I really bared down on them it would measure .0105. I have found over the years that you could get the measurement that you want by cranking down on the thimble a little harder if necessary.
 
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