Member "Steve" took this picture inside his CH4D reloading die for the .495a2:



Here is Dave Manson's chamber reamer drawing:



Do we actually see where the case taper changes at the ghost shoulder inside that die?
Neck-1: .545" diameter
Neck-2: .544" at case mouth of chamber

A-Square cartridge drawing:

we've had this discussion, and my belief is this should be called the neck tension parallel .. as it has no function as shoulder .. yet the whimsy of naming features, nay, in naming rounds, has no limits

quote:

Originally posted by jeffeosso:
we've had this discussion, and my belief is this should be called the neck tension parallel .. as it has no function as shoulder ..

... Well it does come between the neck and the nether region of the cartridge ...

.. yet the whimsy of naming features, nay, in naming rounds, has no limits

Actually, I think we should call it the "Tropic of Capricorn" but since that is already taken,
I reckon to continue calling it what those that came before us called it.

No semantic arguments intended,
just a neat picture from Steve.

Yet the snake has neck and body, yet no shoulders.. Not unlike Yonder cartridge.. Long time gone, in fact, more time did than haven't, sailors said "here be monsters" at the margins of there knowledge

Rip, thanks for posting the picture. not everyday see a photo of a real ghost.
I had sent the Loon Lake drawing to CH4D to confirm their std 495 was the same. cool to see they followed the same, down to the ghost. In follow up phone call, he felt the neck tension parallel or the Tropic of Capricorn or whatever, was a bit dicey, so he included the 3rd die.

I bought CH4D dies last month. Yes, the parallel throat is there. My brass is Jamison from Precision reloading, I bought 100 rounds, they may have 150 left. Full length resizing, gives decent tension on Hornady 570 grain bullets or Cutting Edge solids. They both run closer to .508" than .510. The CH4D expander is marked .508, but leaves a finger push fit. Won't be using it with these bullets. I've made up some dummy rounds. Have the reamer drawing posted by RIP, many thanks. Have yet to ID a barrel shop to bore my Ruger RSM and Manson is 6 months out on reamer production. I would have thought AA would have seen it as a "ghost neck".

OK, semantics it is then, but "jest" some observations and no angst whatever you want to call it.
A real shoulder is a turning inward of the case body taper to a much greater taper angle in the shoulder,
then a turning outward of the shoulder occurs where it turns into neck at neck-1 diameter.
From there the neck is roughly parallel-sided to where it ends at case mouth as neck-2 diameter.

Most chamber reamers will have a .001" taper from neck-1 to neck-2.
The Manson .495a2 reamer drawing indicates this is the case for the standard reamer:
Chamber Reamer Minimums
.545" neck-1
.544" neck-2

Most loaded brass cartridges will hopefully have a parallel-sided brass neck gripping the bullet tightly,
with neck-1 and neck-2 brass diameters being the same, or tapering barely, however much smaller than the chamber diameters for neck-1 and neck-2.
The standard cartridge drawing shows the brass maximums at neck are .002" smaller than the corresponding chamber reamer minimums:
Loaded Cartridge Brass Maximums:
neck-1 .543"
neck-2 .542"

Thus the brass can expand and freely release the bullet on firing.
The 0.001" of neck taper is merely an extra greasing of the skids for extraction in adverse situations.

In real life, brass diameters are usually about .002" to .004" smaller than maximum brass specs anyway.
That works well for mass production rifle and ammo compatibility, easy enough for makers to nail down mass compatibility.

So what we have in the "ghost shoulder" is a "ghostly," hard to see, ending point for the case below the neck.
Shoulder duty for head-spacing is being done by belted base, and there is no real shoulder, true.
But there is a datum line where the neck starts at neck-1, and that is where a shoulder ends.

So we have either a "ghost shoulder" or a "ghost neck-1."
To casual inspection of the cartridge, neck-2 is easily found for measurement, right at the case mouth.
Neck-1 ain't so easy to find.
Spooky, eh?