[twoblink]

Where would you like to punch Hillary Clinton? No!! Just kidding!! That's not the real question! Mod's, don't lock the thread!!

The question I actually have is; with respect to necked down rounds, there is talk of something like whether the round is spaced at the shoulders or at the throat?? I have no clue what they are talking about. I've never reloaded in my life, and never actually cared enough to figure out what they are talking about; but I'm starting to get curious as I talked to my students about (hopefully) reloading my own one of these days...

Someone shed some light who is more clued in then I am? Do you guys know what I am talking about?

[Preacherman]

Moving this one to the Reloading forum.

[Archie]

The "shoulder" of a casing is that part that forms the rapid tapering. The funnel part, if you will. On most high power rifle cases, it's where the main body suddenly gets narrow enough to hold the projectile.

Obviously, if the chamber is similarly shaped, that's what keeps the casing from sliding all the way down the barrel.

Which brings up the concept of "headspace". Proper headspace allows a cartridge to fully enter the chamber, but not have any fore and aft play (doesn't slide back and forth.) (In the real world, there is a thousandth or so play.)

Several different mechanisms for headspace:
1. Shoulder, as mentioned above;
2. Rim, like on a .30-30 or .357 Magnum;
3. Case mouth, like most of the autopistol rounds, 45 ACP, 9x19, .30 Carbine; and
4. Belt, on the "belted magnums" which is essentially a thickened rim.

The "throat" is the part of the barrel leading from the chamber to the bore. This is where the rifling starts, and usually the part that erodes first. No round with which I am familiar headspaces on the throat. The case mouth is right next to the throat, but they are separate.

See if you can find either a Speer, Lyman, Hodgedon or Hornady loading manual. This is discussed in detail with pictures. (Much easier with pictures.)

As for the other question, top of the head with a tire iron.

[Dave P]

"The "shoulder" of a casing is that part that forms the rapid tapering. "

So if that is the shoulder, and neck holds the bullet, why is the HEAD of the case all the way at the other end???

Did someone have their head up their rear when this was defined? Inquiring minds want to know!

[labgrade]

[I]"Did someone have their head up their rear when this was defined? Inquiring minds want to know![/]

Nope, Dave, they, just like sailor-folk wanted a language so they could feel superior when talking to those who don't get it it - yet. ;)

Same thing applies for nomenclature for.38 Special , & .357 Magnum ... all the same caliber. .44 is actually right around .429, or so ...

Not to mention that the Eruo-thing/metric-guys measure completely different than do us USA-folk.

Plug a metric-to-inch conversion factor into a calculator for 5.56, or 7.62mm - it comes out differnt 'cause the metric-guys space on grooves, while we space on bores.

FWIW, different type cartridges head-space on different parts of the brass.

"Normal" bottle-necked cartridges, such as the .30-06, .308-types (rimmed catridges) head-space on the shoulder - that "angled part" closest to the bullet.

Nothing I know of spaces on the throat - unless, perhaps, a space-aged, custum bolt-gun, & that would be counter-productive in short time.

Throat is the "empty space" between the loaded round'sbullet & the distance to where the rifling starts.

More to it all, but hopefully a primer.