.303 Marked Gauge Tool... identity?

Dear brains trust... these pics of a tool clearly marked .303 Case have turned up on another board... Can anyone tell me what it is for so I can end the agony we are going through there.... The was another post from the OP to show a case does not go over the long rod.,.. unsure if it was a new case or a fired case, waiting for an answer to that.... here are the pics... thanks in advance, gents

Attachment 82262

Attachment 82261

Attachment 82260

Attachment 82259

Update to add... this description just got posted there...." it's a gauging tool in the manufacturing process cases before they are drawn out and tapered"

The case in the pic below is a fired, unsized case, so max size... The explanation makes sense... measure the web- periodic testing during a batch lot for setting tooling?

Attachment 82263

Makes sense, to determine the thickness at the primer pocket.

the spindle of which would contact the primer, it seems likely that it is intended to check primer seating depth. It is my understanding that British military ammunition which was loaded with Cordite was necked after the charge was inserted, so that it would have been primed while still un-necked, and the pictured tool seems suited to such a condition.
Alternatively, if the micrometer spindle nose is wider than the primer (can't tell from the photo, though the fact that it is tapered rather than straight makes this less likely), the device may be intended to check the thickness of the case head web.

mhb - MIke

Quote:

---

Originally Posted by mhb

military ammunition which was loaded with Cordite was necked after the charge was inserted

---

That's correct.

Quote:

---

Originally Posted by mhb

the micrometer spindle nose is tapered rather than straight

---

Pic one shows a taper that I believe fits inside the primer pocket. Otherwise I think it would be square.

Quote:

---

Originally Posted by mhb

t it would have been primed while still un-necked, and the pictured tool seems suited to such a condition.

---

But this could be used as easily before priming, after the final draw.

The nose of the micrometer spindle does appear to be tapered, and there may be a recess in its point, which could serve as clearance over the Berdan primer pocket's integral anvil. The tool might be intended to check primer pocket depth, if the dimensions and taper of the spindle nose are appropriate, but without dimensions, it's still a guess.
As a measuring device, it appears best suited to measuring the thickness of the web at the head of the case, and, perhaps, at the bottom of the primer pocket (spindle nose dimensions permitting), since the support post would bear on the inside bottom of the case itself, and the tip of the post is the only fixed reference surface on the tool.
It would seem that a tool intended to measure the thickness of the case head web should bear more broadly on the base of the case, while one for measurement of primer seating depth would better support the case with its base against a reference surface.
Perhaps someone will know what it actually is, or come-up with a better guess.

mhb - MIke

I think it is not likely to be to measure primer pocket depth as there is no datum to measure from- surely to measure the depth of the primer pocket it would need to be measured from the outside of the base in, so an ordinary depth micrometer would do that.

As it takes a measurement between the inside of the case head and the bottom of the primer pocket, I still think web thickness is it's purpose....

No more clues on the other board... will update if there is any. Thanks so far, guys.

Quote:

---

Originally Posted by mhb

there may be a recess in its point, which could serve as clearance over the Berdan primer pocket's integral anvil.

---

That never even occurred to me, I was considering it for boxer primed cases...

would be the actual dimensions of the nose of the micrometer spindle. If, as appears likely, the tool is intended to measure the thickness of the web at the bottom of the primer pocket, why would the spindle nose be tapered? A cylindrical nose of just-smaller diameter than the I.D. of the primer pocket would certainly work as well for the purpose, and the taper (depending on the actual dimensions) might interfere by contacting the edge of the pocket before bottoming - though it is not really possible to determine from the photos, the tapered spindle nose appears to be too large to enter the primer pocket to full depth.
An ordinary depth micrometer would likely need a specialized spindle to clear the Berdan anvil in the center of the primer pocket.
Still puzzling...

mhb - MIke

#8 MHB if you look closely at pic #3 you will just be able to see there is a counter sunk hole in the end of the spindle that would allow it to go over the anvil.
Or further more perhaps it is for measuring the top of the anvil as opposed to the base of the cartridge as if it was to deep would allow the primer to sit a bit deeper which hopefully would still allow ignition but if the anvil was to high then the primer may not sit below the base of the cartridge or worse still proud causing all sorts of issues not only in the field but in production.
That's my take on it.

Quote:

---

Originally Posted by CINDERS

at pic #3 you will just be able to see there is a counter sunk hole in the end of the spindle that would allow it to go over the anvil.

---

You can too...

Back in the day, we didn't reload service ammo.
I cannot see what bearing this has at all.
It would be nice to be able to read the writing on the tool though, it could give an insight into it's use.

As to it being a tool to set up equipment.......it looks pretty rough to me.

I think what the jist of it is its a tool for possibly checking tolerances in the making of the cartridge Muffett as to what end is only being surmised but I stand by what I think it is, also has a scale on the spindle similar to a Redding BR powder throwers so I gather the measurement could be a +- for it to be serviceable.
But as you say if the stenciled writing on the tool be deciphered and put on the forum then this may enlighten all of us.

Quote:

---

Originally Posted by muffett.2008

Back in the day, we didn't reload service ammo.

---

This would have been a factory tool at the first stages of quality control in the factory. It's rough now because it's been allowed to rust.

at the head of the device appears (from the visible markings) to be a true micrometer, apparently American-made by the L. S. Starrett company of Athol, Mass.; measuring to the thousandth of an inch.
I did refer to the (apparent) recess in the nose of the spindle in an earlier post, and mentioned its possible relation to measurement of Berdan-anvilled cases.
There do appear to be other markings engraved on the body of the device, which, if deciphered, might well help solve the mystery...

mhb - MIke

I would hazard a guess that this gauge was used on cases which had not yet had their necks formed.

It might have been used to gauge or at least monitor several features of the case at the same time, but perhaps the height of the anvil in the primer pocket, the centering of the pocket or even the protrusion of the primer if those were inserted before the case was necked?

Time to dig out the old TBSA 1929 I suppose.

What is scratched into it?

Quote:

---

Originally Posted by Surpmil

What is scratched into it

---

Needs a touch with scotchbright...to read better.