Inherent Weakness ?

[Edward Horton]

>>>Your chart on the estimated pressure or force on the bolt face mean nothing because the case is designed to grip the chamber walls and NOT deliver the full force of discharge to the bolt face. Simply put the case acts like a shock absorber and cuts the force in half delivered to the bolt face.<<<

Sorry, the case is not designed to absorb the thrust to the bolt. That it has to in the case of many rifle actions is a throwback to the black powder era's low pressures. You cannot find a design drawing that says that or provides the test specifications that would be used to test for it.

Where do you get your Bovine Scat? Bovine Scat = BS

Information

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[ireload2]

Where do you get your Bovine Scat? Bovine Scat = BS

Where is your engineering drawing that says the case is designed to absorb the thrust?
Some copied and pasted owners manual doe no substitute for engineering data.
The information that I provided about the M-14 National Match rifle and the 7.62mm proof loads is documented by the specifications listed and are located at the US government web site ASSIST.

Did users of Lee-Enfields call off battle when it was raining?

[Edward Horton]

Where is your engineering drawing that says the case is designed to absorb the thrust?
Some copied and pasted owners manual doe no substitute for engineering data.
The information that I provided about the M-14 National Match rifle and the 7.62mm proof loads is documented by the specifications listed and are located at the US government web site ASSIST.

Did users of Lee-Enfields call off battle when it was raining?

Where is your engineering drawing that tells us to oil or grease our Enfield ammunition?

And why didn’t you and Alfred ask this question about inherent weakness at Gunboards, the last postings by Alfred AKA gunnersam was on the 16th and ireloads2 was on the 17th in the Enfield forum at gunboards, very strange.

[Alfred]

Well greasing a cartridge case is not a good idea, and for more than one reason, but fire forming using a spacer ring to hold the case firmly against the bolt face also negates any supposed benefit of the case gripping the chamber wall.

[Alfred]

I just found this unusual entry on the early .303 cartridges and proof testing methods of circa 1896.

Having shown that this method of calculation is perfectly applicable to a 12-bore gun, it will now be shown what the thickuess of the walls of a '303 rifle barrel should be to take the Government Cordite cartridge, which gives a gas pressure, at 1 inch from the breech, of about 15 tons, or 33,600lb per square inch. The diameter of the chamber is about .425 in. ; therefore 33,600lb. multiplied by 425 and divided by 20,00011). gives .714 in. as the thickness of the walls of the barrel; and, consequently, one half of this amount, viz., .357 in , is the thickness of metal which should surround the chamber.


This calculation is made for Cordite, which gives lower pressures than any other nitro powder suitable for this weapon. Some other nitro powders give very much higher pressures ; and, therefore, rifles made to use such powders should be proportionally stronger.

However, sufficient has been shown to demonstrate that had simple calculations, such as here set forth, been made upon the introduction of the '303 double rifle, hundreds of pounds and much valuable time would have been saved to gunmakers. H. P. Phillips.

Sporting guns and gunpowders ... - Google Books
It would appear that a base crusher was not used at that time, pressures being taken at one inch from the breech rather than at the base, and pressure figures gained from this earlier method were far lower than those gained from base crusher pressure guns used later on.
This would have been Cordite Mk 1 rather than Cordite MD of course.

This old book looks like it should be worth a closer look.

BTW
If information is correct its never outdated, if incorrect it makes no difference when it was compiled.
The very wide differences in pressure figures quoted for the various .303 cartridge marks, even the wide tolerance quoted in the manuals, amounting to tons in some cases like the Q series proof rounds, is worth looking into.

Also we can figure that no rifle engineers or designers would depend on a clean dry chamber when calculation necessary strength of an action. A perfectly clean and dry chamber would be hard to guarantee under the best testing conditions and impossible to guarantee with rifles used in combat conditions.

Theres certainly no "friction fit" of a case to the chamber before firing, momentary clinging of a case wall to a chamber wall would be so variable, from one round to another of the exact same manufacture fired on the same day much less cartridges from many different sources fired under widely varying conditions, that no engineer would depend on such a variable to relieve thrust on the bolt when establishing design perameters for the strength of the action.

Some absorbing of energy by the case materials could benefit the action, but its not something that could be counted on. Zero or near zero Head gap clearance of a fire formed case would negate any such expected reduction in bolt thrust. The case wouldn't have more than a few tenths of thousandths of bolt compression to expand into, with perhaps one thousandth or so of clearance if the primer detonation was strong enough to push the case into the chamber against the resistence of the shoulder or spacer ring.

Reducing head gap clearance to the absolute minimum would be of greater benefit in the long run, a finely finished and tight chamber would be another plus, both these were sacrificed with the Enfields in order to allow them to use out of spec ammo and to operate with little maintenance in muddy or sandy environments.
Cordite proved to be a dead end in many ways, it didn't work well with bullets lighter than 174 grains, or diameters of less than .303, the P-13 .276 rifle proved that. No truly high velocity loadings were possible. The MkVII remained sedate in velocity and depended on induced instability of its bullet for maximum effect on living tissue, and this bullet construction limited penetration against obstacles.
The horrific effect of the MkVII on flesh led to mistreatment of British and Canadian POWs on several occasions. Their German captors believed they were using dum dums or other proscribed bullet types. The fact that the British had for many years pre WW1 used such inhumane bullet types against their enemies certainly didn't help.

[Edward Horton]

Well greasing a cartridge case is not a good idea, and for more than one reason, but fire forming using a spacer ring to hold the case firmly against the bolt face also negates any supposed benefit of the case gripping the chamber wall.

Alfred

You can seat your bullets “long” to engage the rifling and hold the base of the case against the bolt face for fire forming.

You can enlarge the neck of the case so the case “headspaces” on the neck of the case and holds the case against the bolt face for fire forming

Or when the chamber and throat will not let you do the above you can put a rubber o-ring around the base of the rimed .303 case to hold the case against the bolt face to fire form the case.

Now put your thinking cap on, how many times have you heard ANYONE saying that shooting fire formed cases that were neck sized only and fit the chamber perfectly caused increased or excess bolt thrust?

How many times did you hear bench rest shooters complaining about bolt thrust and their perfectly fire formed cases in their super accurate bench rest rifles.

Excess bolt thrust is caused by loose fitting cartridge cases not gripping the chamber walls because of oil and grease and slamming into the bolt face.

Fultons of Bisley built special long range Enfields that had headspace set so tight the bolt face kissed the rear of each case when chambered. This had something to do with uniform flexing of the action and accuracy.

In all the books I have on shooting the Enfield Rifle in competition, and setting the Enfield rifle up for competition I have never heard ANY British or Commonwealth shooter complaining about an “Inherent Weak Design”.

[ireload2]

Where is your engineering drawing that tells us to oil or grease our Enfield ammunition?

And why didn’t you and Alfred ask this question about inherent weakness at Gunboards, the last postings by Alfred AKA gunnersam was on the 16th and ireloads2 was on the 17th in the Enfield forum at gunboards, very strange.

Your question about the other forum is none of your business. Your concern with other people's business is abnormal and I consider it a form of harassment. Do you want to stick to the subject matter here?

Where is your military specification that says the case is designed to absorb bolt thrust. You have none today and you will have none tomorrow. You will never have one.

The proofing of the M-14 National Match rifle was fully supported by military specifications and the pressures associated with the proof testing. Since governments are loathe to discard anything, you know that conversion of Lee-Enfields to 7.62 Nato was considered. However from my calculations it appears that 7.62 Nato proof testing is too severe for the #3 and that it is not recommended for the #4 rifle. With a front locking rifle the British government could have milled out the magazine opening and fitted new magazines and gone on. Except with the Lee-Enfield that weakens the rifle.


My use of oil on the brass for fire forming is mostly of my own development.
Itis not restricted to Lee-Enfield ammunition. Therefore it is the result of some thought and creativity and in the manner that I do it, it has been thoroughly tests and found to be safe with a multitude of rifles.

Do you think the Wright Brothers followed existing military specifications while testing their gliders and learning to fly. No. That is why two bicycle mechanics learned to fly before anyone else.

Actually greasing bullets is a long time tested technique that dated back to muzzle loaders. As used today it is present with cast lead and swaged bullets. Residue of the lubricated bullets gets into chambers and on brass and causes no problems.

[Edward Horton]

Your question about the other forum is none of your business. Your concern with other people's business is abnormal and I consider it a form of harassment. Do you want to stick to the subject matter here?

Where is your military specification that says the case is designed to absorb bolt thrust. You have none today and you will have none tomorrow. You will never have one.

The proofing of the M-14 National Match rifle was fully supported by military specifications and the pressures associated with the proof testing. Since governments are loathe to discard anything, you know that conversion of Lee-Enfields to 7.62 Nato was considered. However from my calculations it appears that 7.62 Nato proof testing is too severe for the #3 and that it is not recommended for the #4 rifle. With a front locking rifle the British government could have milled out the magazine opening and fitted new magazines and gone on. Except with the Lee-Enfield that weakens the rifle.


My use of oil on the brass for fire forming is mostly of my own development.
Itis not restricted to Lee-Enfield ammunition. Therefore it is the result of some thought and creativity and in the manner that I do it, it has been thoroughly tests and found to be safe with a multitude of rifles.

Do you think the Wright Brothers followed existing military specifications while testing their gliders and learning to fly. No. That is why two bicycle mechanics learned to fly before anyone else.

Actually greasing bullets is a long time tested technique that dated back to muzzle loaders. As used today it is present with cast lead and swaged bullets. Residue of the lubricated bullets gets into chambers and on brass and causes no problems.

Ireload2

Drink a cup of Earl Gray tea and for a moment try and think like one of our English speaking non-American cousins.

Now think about all these other English speaking Enfield loving people laughing their A$$es off at your statement below.

"However from my calculations it appears that 7.62 Nato proof testing is too severe for the #3 and that it is not recommended for the #4 rifle."

Apparently you are the only person in the world who thinks this way or else you forgot to inform the Australians, the Indians, the British, and the Canadians it would never work.

Signed
Your Best Buddy
Ed Horton
Laughing my A$$ off

P.S. You also forgot to tell our American brothers that the 30-06 was too much cartridge for the M-1917 Enfield. AKA No.3 Enfield

Your “inherent weakness” is just basic knowledge of the Enfield Rifle.

[Dimitri]

However from my calculations it appears that 7.62 Nato proof testing is too severe for the #3 and that it is not recommended for the #4 rifle.

Ed already caught it but the P14 is the No. 3 Enfield, you may be thinking about the "Mark 3" which is the No. 1 Enfield.

L8 Battle Rifles, L39 Target Rifles, Envoy's, Enforcers, L42 Sniper Rifles, DCRA and private gunsmith built conversions all using the basic No4 action that was used in the war, with the conversions done on surplus rifles or with over stock new receivers that were left unassembled after the war have held up just fine, while the Indians instead of adopting the No4 action decided to change the material to make the old No1 Mk 3 action to be usable for the NATO round being in service for many years now.

Dimitri

[Alfred]

Now put your thinking cap on, how many times have you heard ANYONE saying that shooting fire formed cases that were neck sized only and fit the chamber perfectly caused increased or excess bolt thrust?

How many times did you hear bench rest shooters complaining about bolt thrust and their perfectly fire formed cases in their super accurate bench rest rifles.

You've made my point for me, whatever reduction in bolt thrust there might be from a completely dry chamber, which isn't feasible under field conditions any way, is of no significance. The rifles are designed to stand up to the full chamber pressure, not some undefined reduced pressure effect resulting from the case gripping the chamber walls.

A certain amount of locking lug spring back was counted on for reliable extraction of fired cases from the bolt action designs that had poor primary extraction, the LE included. The bolt bounced back driving the tapered case back into the chamber slightly resizing it so it didn't stay stuck in the chamber. You can probably find that information in the books I've linked to earlier, it was a recognized factor from the begining of the use of brass casings for cartridges, and is still factored into action designs.
The more bolt thrust applied to the bolt face the more energy there is for the lugs and locking surfaces of the receiver to apply in loosening the case in the chamber and breaking any grip on the chamber wall from fouling and other contaminants before extraction.

PS

After chamber pressure becomes sufficient to initiate case wall stretching, the case head soon hits the bolt. As pressure progressively increases, it pushes the case head progressively harder against the bolt. Hence, the bolt will progressively compress and the action will progressively stretch until chamber pressure peaks. (Actually, owing to inertia, the case head will continue to push against the bolt, as the bolt continues to retreat, for some time after chamber pressure has peaked.)

Eventually, the bolt will exert more force against the case head than chamber pressure exerts against the case head. At that instant, the bolt will begin to slow, eventually to stop, and then to reverse direction. As chamber pressure continues to plummet, the energy stored in the bolt and receiver will drive the bolt back toward the resting position. In practice, the bolt will hammer the case into the chamber with considerable force; often sufficient to set the case shoulder back enough to assure that case headspace length is shorter than chamber headspace length. As a result, the action will open freely.

While all of this is happening, the chamber also is stretching in both length and diameter. This contributes some to case stretching; it also supplies the energy that allows the chamber to hammer back against the case body, so that it is reduced in diameter enough to assure free extraction.

Depending upon case shape (body taper, shoulder width, shoulder angle), case construction (hardness, thickness, etc.), load variables (pressure peak and duration), action design and barrel design (over the chamber), many results are possible. First, the action can open freely and the case can extract freely. Second, the bolt can turn freely (because case headspace is shorter than chamber headspace) but the case can hang up in the chamber (because relaxed case body diameter is slightly larger than relaxed chamber diameter (the case is an interference fit). Third, the bolt can turn hard (because case headspace length is longer than chamber headspace length) but the case can extract easily (because case body diameter is smaller than chamber diameter).

This partly explains why various chamber and gun designs show different symptoms with loads at similar peak pressure. The classic comparison is the 22-250 versus the 22-250 Ackley Improved (AI). With the former, this rebounding bolt can easily drive the case into the chamber far enough to move the shoulder and solidly wedge the case; with the latter, the shoulder is many times more resistant to being moved and driving the case into the chamber the same distance accounts for many times less increase in case diameter at any given location. Hence, pressure that causes sticky extraction with the 22-250 will show perfectly free extraction in the AI version.

THE GUN
How much the case head moves the bolt face rearward depends upon the following factors:
Shape of pressure curve — a wider curve means more movement (owing to inertia, the case head never has time to move as far as it would if the same peak pressure were applied in a static situation. Therefore, the longer the pressure stays close to the peak, the more the bolt will compress — the farther the head will move);
Peak chamber pressure — force and movement are directly proportional;
Distance between bolt face and locking surface — distance and movement are directly proportional;
Cross-sectional area of bolt — area and movement are inversely proportional; and,
Cross-sectional area of receiver — area and movement are inversely proportional.

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