Just curious how shallow[minimum] shoulder angle can you have on a beltless-rimless case?

The 404 Jeffery has an 8.5 degree shoulder and that is pretty shallow without a belt.

Precise question. Aka "hair splitting." Mauser came up with rimless in "new" brass cases that could stand headspacing on the shoulder and rimmed didn't feed well in the mauser magazine, ergo H&H came out with a belt/ belted case... I am lead to believe that the funnel shape was required to burn the powders of the day...

I am guessing the Hornet, in the US list, is awful shallow, but it has a rim for headspace. Of course, from there you can argue about the "straight cases", aka .38/55, which do taper a tiny bit... So the question comes down to how sharply you wish to split this hair. Enjoy.

One reason for the H&H belted cases had to do with the Brits love for the old reliable rimmed Nitro cartridges. H&H knew that the rimmed cases would not feed thru the magazine rifles and they also knew the old Brits would be leery of a new-fangled cartridge without a rim, so they came up with the belt. It was mostly a sales gimmick. Just like the Weatherby double radius shoulder was a gimmick.

JMHO

Ray

Some where along the road it seems I heard that the H-H case slope and shoulder were to accomodate long sticks of cordite. If not I'm willing to yeild to your expertise. roger

OK I will bite on this one---How about NO shoulder at all???? Then what???

Michael

quote:

Originally posted by Cheechako:

Just like the Weatherby double radius shoulder was a gimmick.

Ray

And here I thought the double radii caused a venurti effect that, in conjuntion with the coriolis force, caused atomization of the nitrocellulos, ultimately converting 110% of the chemical energy into kinetic energy!

quote:

Originally posted by Cheechako:
One reason for the H&H belted cases had to do with the Brits love for the old reliable rimmed Nitro cartridges. H&H knew that the rimmed cases would not feed thru the magazine rifles and they also knew the old Brits would be leery of a new-fangled cartridge without a rim, so they came up with the belt. It was mostly a sales gimmick. Just like the Weatherby double radius shoulder was a gimmick.

JMHO

Ray

Unfortunately, you are only partially correct, the belt was no gimmick, rimless cases were already in existence when the first belted case came about, and no it wasn't by H+H either.
The belts sole purpose is for positive headspace control, not strength or any other myths associated with it.
H+H initially tried the beltless/rimless path for their new magnums, but found positive headspace control a real problem, the firing pin blow would push the cases further into the chamber because the shoulder didn't support the case correctly and it would crush lengthening headspace. The belt, which they took off another cartridge design, stopped this dead, it works exactly the same as a rimmed case but without the problems of having a rim protruding .020"-.050" into the magazine space and you don't have to stagger load in the magazine.
The reason that Roy Weatherby designed his cases with a radius shoulder is because it is said to improve gas flow, and enable a more efficient burn, which I cannot deny, because the velocities you get with Weatherby rounds defies belief in some circumstances.
The 375Weatherby is a good example, it has 10gr's more capacity than the H+H but gets 200fps more velocity with less pressure than the H+H uses.
So, no I don't think it is/was a gimmick!
416RigbyHunter.

416

Unfortunately, you are only partially correct. The first belted, or Double-flanged cartridge, was not by H&H (I never said it was) but they (H&H) were the first to develop it as a commercial success. H. W. Holland filed his patent in 1904 and his application stated, as you said, that the belt, or as he called it, "a small ridge in front of the extractor groove", was to prevent the cartridge from entering the chamber too far. The thinking in those days was that making bottle necked cases that seated on the shoulder had not advanced enough to be reliable. This in spite of very successful cartridges such as the 7x57 and 7.92x57 Mausers. Had Holland simply increased his shoulder angle from 15 to 20 degrees his headspace problems would have disappeared.

But, even if Holland had trusted shoulder headspacing and designed his new rifle and cases as rimless bottle-neck, he still had to satisfy his customers. The old Brits, used to their large flanged cartridges, and set in their ways, were where the money was and H&H weren't about to take the big gamble, especially on an idea born on the Continent.

As far as the 375 Weatherby, I would certainly hope that a case with 10 grains more capacity would result in more velocity. After all, it is nothing more than an Improved 375 H&H. But much of the increse in ballistics also comes from increased pressure. The excess freebore of the Weatherby's is there for good reason. Other improved H&H wildcats use the conventional shoulder shape and they manage the same velocities as the double radius.

In my opinion, all of the gimmick shoulders are just that. Whether double radius, PMVF, CCC, SMc, or any others you can mention, none can live up to their claims when fairly tested.

Again, JMHO

Ray

Question...

What case body length and angle would be good enough for a ghost shouldered case for reliable headspacing????
Just imagine the shallow shoulder IS the body with a neck and no other means of headspace other than case taper.

8 degrees works on the 404 Jeffery sooooo...

How about a 4 degree case taper and a long neck? Imagine a 2.1" or a 2.5" RUM based case that uses the taper for headspace.

First belted cartridge:
Sylvester H. Roper's .41 Roper, 1866 patent, USA, reloadable steel case for a revolving rifle, actually produced from 1867 to 1868 in Amherst, MA (Roper Repeating Rifle company) and 1869 to 1876 in Hartford, CT (Roper Sporting Arms Company). Shotgun repeaters too, with belted steel cases and revolving actions.

22 hornet has about a 5.5-degree shoulder, but headspaces on the rim.
470 NE has about a 7.5-degree shoulder, rimmed.

I don't know of any more slope-shouldered, rimless cartridge than the 404 Jeffery with about 8.5 degrees.
Will keep an eye peeled. I have two of the George Hoyem volumes (I and III were all I could find) on "Small Arms Cartridge Development" on the way.

You cannot find everything on the internet.

Cheechako,
If you had of read my post, you would have seen that the 375Weatherby produces the increased velocity with LESS PRESSURE than the H+H round.
I know this to be correct, because I have pressure tested both, with modern loading techniques and standards.
The freebore is there to REDUCE pressure, which believe it or not, increases velocity with a more subtle pressure curve, which acts on the bullet longer, and is enhanced by the radius shoulder making a smoother transition of the gas volume into the bore.
416RigbyHunter.

I only know what I read but it has been said that Roy Weatherby's reasoning behind the radius shoulder was not likely for increased performance but rather because reamers would be very hard to reproduce thus making it difficult for anyone else to chamber his cartridges.

quote:

Originally posted by Juggernaut76:
Roy Weatherby's reasoning ... radius shoulder ... reamers would be very hard to reproduce thus making it difficult for anyone else to chamber his cartridges.

Have read that too.
The double-radiused shoulder was venturified hype from Roy, with a wink and a nod.
Modern reamer makers like Dave Manson have no trouble duplicating the "magic."