I finally got around to making a necking up tool. My first test was a berdan PMP case that showed no visible sign of being fired. I annealed the neck and shoulder to dull red and expanded it all the way to .425. I have no idea what the spring back is as the expander is still in the case.

Now the question. How concentric can I expect the wall thickness to be? The case shortened from 56.5mm to around 54mm. The mouth is not very 'sqare' so I would expect the neck wall thickness to be somewhat uneven. Does this matter when the wall is getting down to 0.25mm (.01") thick?

I am trying to figure out whether I should go all the way to 41 cal and have a cartridge with a 0.6mm taper, which is less then the 303 Brit, but would create a shorter '405 Winchester' clone - the case would be 12mm shorter. Or, I could go to the .40 cal and keep the same body taper and suffer a shortage of bullets (I would be casting them anyway), or go to the 37 Rimmed, which will give the case a tiny shoulder (from 10.05 to 10.2). This tiny shoulder would likely blend in anyway as the case thickness would inrease where the original shoulder once was, leaving a taper neck exterior. With the .41 option, the case body taper would end a bit further back and go parallel into the neck (again, a slight taper would remain on the exterior).

Originally, I had thought of shortening the case to the original shoulder/body junction, but now knowing that I can keep the full length, I can operate at lower pressure for case (and my shoulder) life while the shortened version would headspace on the case mouth

Your thoughts and ideas would be appreciated.

(The 35/303 had not been ruled out but is harder to justify in the light of the existing 303!)

Well, of course, ALL 303 cases are before they are "rolled" to prodcue the neck 2 1/2" brass 410 catridges. And, as you know, 410 "guard" rifles were produced for Indian use. The acrtridges being not actually 410 shot gun cartridges but un-rolled 303 cartridges.

I have cut off a 303 at the shoulder to produce a similar sort of thing.

My advice would be to see if you can "intercept" 303 cases BEFORE they go to have the necks and shoulder rolled into them.

I don't know what Bruce Betram makes. Or how close to size is something like 375 Winchester?

The other route, maybe, again I'm not looking at a size chart, is to turn the belt off 300 H & H or 240 Weatherby or something and use them?

I just acquired another M95 Dutch Mannlicher action and have been going through some of the same mental gymnastics.

With the .410 version I could use .41 magnum pistol bullets or cast BPCR bullets normally intended for the .40-65 Win. I don't see myself going to Africa though. So the heavy lack of heavy jacketed bullets are of no concern.
If used straight it would be sort of a .44 Magnum double extra long with no body taper.
Existing dies could be used but short bullets do no feed well in the Mannlicher.
A .375 might be a better compromise since there is a wide range of bullets available both jacketed and cast.

In the US we have the option of a slightly longer version using .30-40 Krag brass. However for the Mannlicher the rims have to be turned.


Headspacing a long case on the mouth is a problem unless you maintain very little clearance between the loaded round and the chamber. When the case is fired it expands and gets shorter allowing the primer to back out.
Why headspace on the mouth when you have a rim anyway?

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Why headspace on the mouth when you have a rim anyway?

Ah! Right! I did say headspace on the mouth of the shortened version - that's because there would be enough case thickness in that area. The idea is not actually to 'headspace' but rather to control case elongation. So the case would be cut to closely fit the chamber and allowed to expand on it's own (about .05mm clearance). Normal headspacing would still be on the rim. This would not be possible with a full length case due to the thinness of the neck. But then case stretch should be avoided by virtue of the lower operating pressure. Well, that's my theory, anyway! (I do this with my 22 hornet. It works just fine. But then I do not size the hornet necks so it can engage the neck step - which is a 45 degree chamfer but it only puts a slight 'crimp' on the mouth. Not enough to prevent placing of a paper cup and seating of the bullet. Case life is rediculouse - like forever! )

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Originally posted by 303Guy:

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Why headspace on the mouth when you have a rim anyway?

Ah! Right! I did say headspace on the mouth of the shortened version - that's because there would be enough case thickness in that area. The idea is not actually to 'headspace' but rather to control case elongation. So the case would be cut to closely fit the chamber and allowed to expand on it's own (about .05mm clearance). Normal headspacing would still be on the rim. This would not be possible with a full length case due to the thinness of the neck. But then case stretch should be avoided by virtue of the lower operating pressure. Well, that's my theory, anyway! (I do this with my 22 hornet. It works just fine. But then I do not size the hornet necks so it can engage the neck step - which is a 45 degree chamfer but it only puts a slight 'crimp' on the mouth. Not enough to prevent placing of a paper cup and seating of the bullet. Case life is rediculouse - like forever! )

If you do that then make the end of your chamber a square shoulder like a Mauser chamber.
Sort of the belt and suspenders approach?

Isn't it a bit early in Kiwiland?

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If used straight it would be sort of a .44 Magnum double extra long with no body taper.

Due to the case wall thickness, there might be just the slightest taper. And that one is on the cards too! I'm just not sure how well the Lee Enfield would feed a straight case and I would be likely to lose the magazine ten round capacity. It would simply be a 444 Marlin on a 303 Brit case.

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If you do that then make the end of your chamber a square shoulder like a Mauser chamber.
Sort of the belt and suspenders approach?

Yes, that is the idea. It's what appeals to me about shortening the case. It might also make for a more efficient cartridge for a shorter barrel but then it might also limit the powders I can use - meaning that with the longer case, I could use my 'normal' 303 powder for low pressure loads but would get quite a muzzle blast and flash! Which might actually be quite fun!

That leads to a question - how would powder efficiency be influenced by using, say the same charge of H4227/AR2205 in a shorter case versus the longer case? (Pressure is not going to exceed the SAAMI 43,000 CUP).
We are at 10:50 here (am).

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Originally posted by 303Guy:

quote:

If used straight it would be sort of a .44 Magnum double extra long with no body taper.

Due to the case wall thickness, there might be just the slightest taper. And that one is on the cards too! I'm just not sure how well the Lee Enfield would feed a straight case and I would be likely to lose the magazine ten round capacity. It would simply be a 444 Marlin on a 303 Brit case.

Yes but it would be a truly straight case so you could use pistol carbide dies. However you would have many more feeding issues with the Lee Enfield than I would with the Mannlicher.

The Lee Enfield magazine has so much taper that it does not work well with the larger rounds with out significant modification.

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ALL 303 cases are before they are "rolled" to prodcue the neck 2 1/2" brass 410 catridges.

Is this case staight (or nearly straight) in the interior, giving the exterior a slight taper, before being sized down to 303 Brit? (I believe the cordite loads were made by charging the case and placing the wad, at this stage? That might be the reason for the wad? Or is the wad just simply to allow the sealing of the case with butimen before bullet seating?))

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Originally posted by 303Guy:

quote:

If you do that then make the end of your chamber a square shoulder like a Mauser chamber.
Sort of the belt and suspenders approach?

Yes, that is the idea. It's what appeals to me about shortening the case. It might also make for a more efficient cartridge for a shorter barrel but then it might also limit the powders I can use - meaning that with the longer case, I could use my 'normal' 303 powder for low pressure loads but would get quite a muzzle blast and flash! Which might actually be quite fun!

That leads to a question - how would powder efficiency be influenced by using, say the same charge of H4227/AR2205 in a shorter case versus the longer case? (Pressure is not going to exceed the SAAMI 43,000 CUP).
We are at 10:50 here (am).

H2227 is would work at the top of your pressure down to about half that pressure since it is commonly used in handguns at those pressure ranges.
You might look at .444 Marlin, .45-70 and similar cases using 4227 loads. (BTW it has been said that H4227 was discontinued in the US by Hodgdon after they saw the volume of IMR 4227 being sold.)
Lighter loads would require something like the pistol powder Unique or similar.

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The Lee Enfield magazine has so much taper that it does not work well with the larger rounds with out significant modification.

That's what I thought - thanks! I will make a few dummy chambers and try out the various 'chamberings' as I get closer to finalizing my choice.

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And, as you know, 410 "guard" rifles were produced for Indian use.

I had forgotten about that! That would make that one an ideal choice.

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The Lee Enfield magazine has so much taper that it does not work well with the larger rounds with out significant modification.

With one exception...the Ishapore 308 and possibly the 7.62mm Sterling or British Army L65 marked magazines for the L42 sniper conversion of the No4(T).

Note that in most 7.62mm conversions of the No4 some removal of metal in the receiver is required.

I think that a .410 Ishapore is the way to go!

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Originally posted by enfieldspares:

quote:

The Lee Enfield magazine has so much taper that it does not work well with the larger rounds with out significant modification.

With one exception...the Ishapore 308 and possibly the 7.62mm Sterling or British Army L65 marked magazines for the L42 sniper conversion of the No4(T).

Note that in most 7.62mm conversions of the No4 some removal of metal in the receiver is required.

I think that a .410 Ishapore is the way to go!

Was the Ishy .410 really a repeater?
I mean it is a .410. It is not like it was a real gun. Seems it would be more likely a single shot.

BTW you can cut much on the magazine well side walls of a Lee Enfield with out weakening the action.

The only reference I found with a quick search was of a single shot 410 shotgun for prison guard duty.

I see that to retain the full body taper up to the shoulder I would have to use a .380 bullet. I don't know if there is such a thing - there used to be. I don't know whether there is such a thing as a .400 bullet either. That would begin the neck a little further back but not much. Maybe far enough back to result in the loss of one round in the mag without modification. If I will lose one round capacity then I might as well look at the .41 bullet. The magazine might have to lose the side ribs.

303 Guy,

the cartridge you want was introduced in America in 1882 as the .40-60 Maynard. 2.20" long and can be loaded with .40-70 Sharps Straight dies. Uses a .410" diameter bullet. It enjoys a modicum of success today in the BPCR Black Powder Cartridge Rifle Silhouette matches. No special forming dies needed, they just fireformed using a cast bullet and medium pistol powder load. It's a snap if you have access to a lathe. Take the .410 diameter bullets and turn about 1/8th inch on the back to fit the .303 case. It sits against the chamber throat and holds the case square on firing.

Rich
Buff Killer

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40-60 Maynard ... No special forming dies needed, they just fireformed using a cast bullet and medium pistol powder load.

Now there's an idea! There is probably no reason those 'case forming' bullets should not shoot straight too! Still, making an appropriate expander plug is a breese too.