Safe load for .303 British SMLE

[Ballistics in Scotland]

Allegedly 12 grains of Unique in a .303 Martini Henry

Note that it was proof tested, but the stamps on it show the test was a black powder proof test, NOT a smokeless powder test.

That is a very spectacular burst, but I would be surprised if there wasn't some cause other than being for black powder.

The gun is Belgian, and "PV", for "poudre vive" means it was proved for nitro powder. The crown on the oval "ELG" means it was proved in 1893 or later, at which time the use of smokeless powder in a .303 would have been taken for granted.

Even in British manufacture, although nitro proof was only introduced in 1904, no .303 barrel was explicitly intended for black powder. They knew before the adoption of the Lee-Metford in 1888 that the French had a "chemical powder" which gave enhanced power, and the only question is whether they knew it also gave enhanced pressure. I think they did, for the sights f the Lee-Metford were graduated from the start for a flatter trajectory than could be obtained with the stopgap solid black powder pellet they used.

In fact the secret of the Lebel were pretty well out, at a time when French soldiers were threatened with ten years in jail for opening a cartridge - and being French, probably all did. There is a most interesting story which may even be true. In 1887 one Schnabele, who sounds like an Alsatian, deserted to Germany with his rifle and ammunition, and offered the to the War Ministry for 20,000 marks. They told him to go away and not be so silly, as the rifle was little more than a smallbore Kropatschek. So he knocked on Bismark's door, and the old man brought the Ministry into line. This illustration was published by Professor Hebler in Leipzig in 1890, and bears the British Intelligence Division's stamp for 1891. I don't have the book, and am not likely to get it, but the pressures of smokeless in smallbore military rifles were surely well known, and black powder cartridges made for them entirely out of use, when this Martini was made.



Many thousands of rounds of MkVII ammunition have been fired in Long Lee-Enfields, without mishaps that I have heard of. If it comes to that, unless the burst Martini was a wallhanger from new, it must surely have fired a lot of cartridges with higher pressure than 12gr.of Unique. When the British proof houses decided to prove the No4 but not the SMLE for 7.62x51, it was due to cracks developing in the lighter SMLE receiver, not failures of the barrel.

Belgian proof was pretty reliable, and Martinis were one of the firearms they did best. I suppose it is possible that a barrel with seams or inclusions might pass proof and let go later, but I don't see any part of the fracture which doesn't look like new-riven metal. My guess is that a doiuble charge of Unique is the most likely cause, and second is a "misfire" ejected without noticing that a primer with no powder has left a bullet lodged just ahead of the chamber.

[leebuilder]

I agree. That was catastrophic to part a barrel like that. Even a weak section would not burst like that with out prior sign of impending failure. The fracture lines are near perfect like a sudden burst occurred and excceeded the limit of the chamber. I am leaning toward an obstruction.
I hope no one was hurt.
Be safe

[Ballistics in Scotland]

If it was an obstruction it could only have been very close to the chamber, which rules out mud picked up in the muzzle, and cleaning materials would seem improbable. A bullet an inch two down the bore would fit the bill nicely, but I have my doubts (which I am not going to test) whether a bullet hard up against the one in the cartridge would do it.

I've quoted before the example of a friend of a much older friend in my 1950s childhood, who attempted suicide on India's plains, and just to make sure, filled the bore with water. He decided at the last moment that this world might improve, while death certainly wouldn't. But in his nervous state he tripped the trigger anyway, and shot off most of one ear. He woke up with the godlike figure of the regimental sergeant-major by his bedside, assuring him that he wouldn't be dismissed the service for attempting what was then a criminal offence, but he would be put under stoppages for five pounds ten shillings, to pay for the rifle.

The point, and a great grievance to him, was that it wasn't actually burst by this bullet and water weight of several hundred grains. his eardrum wasn't burst either, suggesting that the greatly extended bore time had permitted the gases to cool, and perhaps condense. This is another thing I would decline to test, as results may vary. But in general it is deceleration of the bullet that causes obstruction bursts, not preventing it from accelerating.

[john.k]

Sooner or later ,everyone who uses reduced loads of fast powder in big cases will have a double charge......most times we are lucky ,and the result is only a stuck and deformed case....But IMHO ,a 24gn charge of Unique would be 70-90,000psi ,probably a pressure 20th century military rifles would withstand,but not a 1890s barrel.....possibly with a weakness in the steel from heating.

[303Guy]

Not to mention the shock from a near detonation.

Here is another split chamber. And action. And everything else.

http://cdn0.wideopenspaces.com/wp-co.../12/762d15.jpg

[john.k]

I think that M14 is a Chinese barrel let go.....still the Martini action in the pic showed a remarkable resistance to splitting ,mainly because its not possible for a case to let gas go into the reciever......even the extractor cut is a very close fit in the barrel,and the extractor arms are backed up by steel walls...If you look ,there is a spectacular picture of an Italian Sharps with a burst barrel on this site....so even modern steel can let go...if you read Hatcher,he quotes a 30-06 case full of Bullseye as the highest pressure available for testing,about 130,000 psi......which a Garand action could hold,and presumably the barrel also.

[leebuilder]

I have seen 3 m305 or Chinese m14 clones they all failed under normal shooting (or so the owners claim)
They did not fail catastrophically as in the pic but did bend the op rod, barrel, receiver, bolt and other bits and no barrel burst like that. One failed after a hundred rounds of factory ammo, one shot out of battery with fancy factory match ammo the last I didn't ask. Heard of a few more cases and did not pursue it, only explanation is "Friday night at norinco". Heard of the new powder metal, sinthered, molding technology used in the bolts manufacture parting off at the bolt lugs under normal shooting conditions and ammo.
I have one I have at least 8000 rounds plus through it, it's a bit loose now but no signs of ammo slamming the rifle apart, I guess mine was made on Tuesday morning.
That was a catastrophic failure and hope no one hurt.
Be safe

[303Guy]

I have heard of a Lee Enfield (I would think an SMLE since it was from a WWII armourer - my uncle, although he never said it was) that apparently had a pull through cord left in the bore that split the barrel from chamber to muzzle. I think it was a single split if memory serves. I don't know how that was determined though. How does one chamber a round with a pull cord in the chamber?

We've all heard of 270 cartridges being fired in 308's. In one case the rifle held but in another, the receiver ring split and released the barrel which landed halfway down range. It was a factory test firing so it was by remote - no injuries. The barrel was still serviceable! The action was a Musgrave model 80 (designed by my uncle and his team).

We've also heard of destruction testing on Arisaka's in which the case was filled with BullsEye. The brass flowed all over the place and jammed the action but it held, as did the barrel.

[john.k]

Stuck pull thru s was a very common blowup in a smelly......Some one I know did it using a bit of blanket as a patch,the old dodge with a pullthru was to tie the cord around something ,if it got stuck,and pull the rifle with all your weight.If the cord broke,well.........So a lot of shooters decided to blow it out.Usually resulted in a blown out bolthead,and an amputated barrel.....at the very least a egg bulge in the barrel...But in those days smellys were $2 each,so no one cared much,if their face was still there after the bang...Iv seen dozens of blownup smellys from just that.

[Ballistics in Scotland]

If they had paid $2 and got to walk away (as most people do after firearms failures) fine... till the next time. If they were in the service and got it free, though, death might seem sweet.

I think there is a pretty good chance that it would be blown out with no damage done by a de-bulleted cartridge. But it might not, and I wouldn't call "pretty good" good enough to try. Those cords are natural fibre, and very often rotted by decades of untouched storage in the butt socket.