While many folks like to discuss the problems of belted cases, haven't heard anyone argue that the belt was insufficient for headspacing a cartridge, e.g., the 458 Win Mag.

However, folks frequently worry about too small a shoulder being adequate for headspacing some cartridges, e.g., 375 Whelen.

If the shoulder is at least the same additional size as the belt on a magnum case, shouldn't it headspace just as well ?

This is a question. Have no data of my own to offer.

The only positive that I can see for using a belted case is that it makes it impossible for one to end up with an excess headspace condition. Yes, you can move the shoulder back a lot more than needed but the case head will always be near the bolt face.
A minimal shoulder should work fine unless the shoulder is moved back a lot more than needed.

A belt is a truly sharp, abrupt, (nearly) square shoulder for head spacing.....much like the case mouth of the ACP cartridges.

A shoulder usually is at a (blended) angle and much less reliable stop for headspacing unless it's of significant size.

IMO a shoulder of the same size as a belt is not as good a headspace characteristic as a belt.

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IMO a shoulder of the same size as a belt is not as good a headspace characteristic as a belt.

My 40 degree shoulder on my 416PDK will stop the case and in a 411 version would have the same amount of surface area as a belt. It works and give me proper headspace. But I feel the only way a minimum shoulder will give you the same stopping capacity as a belt is for it to be 90 deree.

...if it has more bearing surface area than a HH belt, it will work... I haven't had any issues with the 470AR, which is the least headspace of anything I have designed.

the HH belt IS small..
.532
-.510
=.022 TOTAL


Which has nearly this per side, but more bearing surface


same, but more still, on the 500 AR


jeffe

Hammer,

The shoulder only has to be sufficient enough to prevent the case from moving forward from the strike of the firing pin. The steeper the shoulder the less likely it will move.

Measure the diameter of the belt on a .458 Win Mag case and that of the chamber and there will likely be even less contact, but as was mentioned above, the belt is a square shoulder and less likely to deform and move than one that is tapered. Remember, all it has to do is withstand the initial strike. The igniting powder will take care of the rest.

The beauty about the belted cartridge on lesser calibers than the .458 Win Mag is, once it is fire formed to the chamber, you will be able to headspace off the shoulders like a normal case which can only help accuracy.

The metal in area of the belt is much heavier than a shoulder and behaves more like solid metal. If manufactured in the proper location the belt is permanently correct.

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Originally posted by Hammer:
This is a question. Have no data of my own to offer.

Me also. Some characters on AR had me convinced the "belt" was vertually useless, as it was always made too short/small whatever which always gave some excess headspace.

Therefore everyone quickly changed to headspace off the sholder (if any), which creates its own correct headspace after one fireing.

Also I would immagine, if a rifle had excessive headspace from wear or lug setback ect. I can't see how the belt will correct that.
As for my .458WM, I still havent got my head around any headspace problems regarding fired brass. At the moment I'm just PFLS'ing and hopeing for the best.

btw, I, myself, am indifferent to belt or no belt. for example, the 550 express has a belt. the 458 lott and ackley are fantastic rounds, and my 458 AR matches them, with no belt... doesn't matter which one you go with, the bullets come out the same.

jeffe

Why has nobody made cartriges with shoulders shaped as belts? Yea, the shoulder would be definitive, but it should keep the streching to a minimum, thus giving normal case-life......?

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Why has nobody made cartriges with shoulders shaped as belts? Yea, the shoulder would be definitive, but it should keep the streching to a minimum, thus giving normal case-life......?

Feeding issues???

Screw it, neck size and the argument goes away....

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Screw it, neck size and the argument goes away

That's like saying the push vs CRF arguement could ever go away.

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Originally posted by Hammer:
While many folks like to discuss the problems of belted cases,

If you question the folks who "claim" the Belt causes any kind of problem, you will quickly determine they really don't know what they are talking about.

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haven't heard anyone argue that the belt was insufficient for headspacing a cartridge, e.g., the 458 Win Mag.

And you won't because it would be Full-of-Beans.

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However, folks frequently worry about too small a shoulder being adequate for headspacing some cartridges, e.g., 375 Whelen.

If the shoulder is at least the same additional size as the belt on a magnum case, shouldn't it headspace just as well?

Yes.

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Originally posted by Bent Fossdal:
Why has nobody made cartriges with shoulders shaped as belts? Yea, the shoulder would be definitive, but it should keep the streching to a minimum, thus giving normal case-life......?

Historically, there have been a few. I don't have the names handy (didn't anticipate this question), but if I run across them again in the next couple of weeks will start a thread and post same. Then there have also been some relatively recent wildcats (last 50 years) that come very close.

I suspect the only repeaters they would be practical in would be those which use a ramp to raise the center of the cartridge fully up to the longitudinal center axis of the bore, then use the breech block(bolt?) to push it straight forward. Otherwise the shoulder might hang up pretty frequently, I should think.

But I think Jeffe's answer may be the meat of the whole thing. I.e., belt or no belt doesn't make much if any difference in real life, so long as the shoulder is big enough to resist the firing pin blow.

Incidentally, the brass in cartridges is generally strong as heck! Ever try to chamber a rcartridge with the shoulder just a couple of thousandths longer than the available chamber?

Even with the camming advantage of a well-designed bolt action it can be danged near impossible. In a falling block single-shot action, it can BE impossible.

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Originally posted by Alberta Canuck:
But I think Jeffe's answer may be the meat of the whole thing. I.e., belt or no belt doesn't make much if any difference in real life, so long as the shoulder is big enough to resist the firing pin blow.

Are you sure it was jeffe that said that?

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Incidentally, the brass in cartridges is generally strong as heck! Ever try to chamber a rcartridge with the shoulder just a couple of thousandths longer than the available chamber?

You are correct However since shoulders have angles locating them can be a problem in both the chamber and the cartidge case. The 300 H&H has an adequate shoulder to headspace on. However the angle is so small that if you miss a diameter just a little the run of the angle is very long giving a lot of mismatch in the length of the datum points.