Paper Tube (Cardboard)

Gentlemen, thank you all for your help, advice and information thus far. I will investigate the legality of producing the cases before proceeding any further and will post an update in due course. In the meantime I would welcome any further input. Robert Butler

Further to the various posts concerning the proposed "manufacture" of pin fire cartridges. The British Association for Shooting and Conservation confirm it is legally permissible to manufacture ammunition for a weapon on my shotgun certificate and therefore not legal to manufacture for others. The project is stillborn. Thank you all for your contributions and warnings. Robert Butler

I see no problen if you machine the end caps and pins and your friend assembles them to tubes and loads them.
There are no restrictions on empty case parts.

Robert G8RPI.

This event is patently spurious. As the charge in a cartridge is enough to eject shot and wad from the barrel removing the shot would not cause a wad to be let in the barrel. If they removed the propellent s well, why put the wad back and the noise would be less thn a "banger"
Maybe he used an alarm or saluting blank but they don't have wad.

Not sure about that. It's reasonably common for a projectile that's too light for a given burn-rate of propellant to result in incomplete combustion of the charge. Results of a followup shot could be unpredictable without knowing a lot more detail about the state of things after the first shot, but there is a condition known as 'detonation' where a quantity of propellant is distributed through a space in a manner that generates a shockwave passing through the granules that causes them to process into gas very much faster than in the normal burning process. Effectively the dispersed charge behaves like a high, rather than a low explosive.

This description is not really definitive because even authoritative sources don't seem to be able to describe the phenomenon with exact clarity, or at least none that I've read - probably because it's intermittent and sometimes hard to reproduce. Whilst it's generally far more reliably dangerous to change the projectile weight upward than downward, the detonation phenomenon occurs AFAIK more often with light charges and projectiles.

’Patently spurious’ eh?

Perhaps you know little about the wadding in a 12 gauge shot-shell?

Perhaps you know nothing about shotguns and barrel obstructions?

Having seen the effects of any obstruction in a barrel, I had no reason to disbelieve the shooter. His wife corroborated the event. The gun was not an old weapon and was chambered for 3” cartridges - possibly part of the problem. It only needs an over-powder wad - not the main driver wad - to be left in the barrel to cause the damage.

And he did not remove the powder charge or wadding from the cartridges - just the shot charge. A primer makes a noise, but not better than a firework. I’ve done that before now. Usual was to hit a primer with a gammer - the only danger is metal slivers exiting the strike sideways.🙂

There was the possibility that it could have been unburned powder, but as I posted “ it was attributed to” a wad causing an obstruction. I’ve fired a shotgun with quite a bit of unburned powder residues - left in the barrel after using a short sleeve for firing 0.410 cartridges in the 12 gauge - with no problem. Some reloads actually used four, maybe even five, separate wads in each reload. It just depended on the load and tube length, along with the type of propellant used, but maybe you would not know that?

A few ‘non-spurious’ facts. The first 12g shotgun I used risked the barrels parting as the top rib became detached, so I moved on to my father’s slightly loose hammer gun. I’ve still got it but it now ‘kicks’ much less after a gunmaker tightened the action back in the 1970s. Yet another gun I used suffered from separating barrel tubes during use while the top lever spring was being remade for my father’s gun (it had been used for some time with the lever held in place with a couple of elastic bands - two as a precaution of one breaking while out shooting). The things we used to get up to in our youth.

The main point of this post is that I don’t tell lies.  I have lived a ‘practical’ life, not a theoretical one.  You may not believe it but that is your problem.  Best kept to yourself?

Edited By not done it yet on 09/03/2020 19:43:14

Easy guys.

"patently spurious"? Is that the English language?

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It seems to have been in use for a while.

MichaelG.

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https://lmgtfy.com/?q=%22patently+spurious%22

Edited By Michael Gilligan on 09/03/2020 20:56:55

This one's a puzzle that got me thinking about cause and effect.

Unfortunately, the evidence is incomplete. We don't know how the cartridge was modified, or the circumstances in which it was fired, or which part of the gun broke. Perhaps NDIY can provide more detail?

Where the gun broke is relevant because thats the point at which pressure over-stressed the barrel - an important clue. In normal operation maximum pressure is at the breech. Thereafter it must drop along the length of the barrel and fall to zero just outside the muzzle.

• If the gun failed at the breech, the cartridge is suspect.
• If the gun failed further along the barrel, an obstruction is suspect. (Though I explain later that air alone might be sufficient obstruction.)

The circumstances are relevant because there's a hint of revelry in this story! Gun fired as a Banger, Hmm?

Celebrations often involve carelessness, and diminished responsibility. During the high-jinks, maybe the muzzle picked up mud, or a twig, or Mr Anonymous popped a real banger down the barrel for a laugh. The owner may have believed his blank cartridge made the gun safe, and didn't check before firing it.

The cartridge has to be considered too. Maybe the lead shot was replaced with more powder, even something unwise like firework gunpowder. Or a gap was left between two wads.

I first assumed removing shot from a cartridge would automatically reduce pressure in the gun. Common sense suggests more pressure is developed pushing a load than moving gas down an empty tube. However I have a low opinion of 'common sense', and this might be an example.

The gun is powered by a chemical reaction turning a solid into a gas, also producing heat greatly expanding the gas. It does so at a speed related to the chemistry, barrel volume, and work done moving the shot.

Converting heat to work follows the usual heat engine rules. Heat converts into kinetic energy, accelerating the lead-shot. Conversion cools the gas greatly and thus reduces pressure in the gun. If a gun is fired without a load, it will get much hotter, hence the pressure may be higher too. Worse if the charge also burns faster than normal.

As the reaction is faster than the speed of sound, air inside the barrel acts as a spring, causing waves to bounce inside the barrel, causing unusually high pressures at the point of reflection. If the reaction is much faster than the speed of sound, air behaves more like concrete - it can't get out of the way fast enough.

Shock-waves matter more than average pressure and explosive speeds are relevant. I imagine a sharp pulse of energy being applied to the barrel by the modified cartridge rather than the normal well-engineered expansion.

I suspect reflected pressure waves do most of the damage when a barrel is obstructed, rather than shot colliding mechanically with the blockage. If so not necessary for a barrel to be completely blocked to over-stress it: only enough to cause a reflection. At the point of reflection the reflected pressure adds to the existing pressure. If the metal's elastic limit at that point is exceeded, the barrel will break.

All conjecture, but I can just about see how firing the first blank might have cracked the gun at a particular point, and firing the second blank repeated the blow in the same place without a wad or other obstruction. (I agree they would turn a risk into a dead-cert.)

Ignorantly modifying cartridges could take a gun for a walk on the wild side. Mick's suggestion that the first blank left unburned powder in the barrel is also possible. Burning loose powder could also put abnormal pressure on a weak part of the barrel.

Proof testing consists of firing guns with an extra heavy charge? This only tests the breech end of the gun, which is made considerably stronger than the muzzle end of the barrel. Much less pressure will damage the thin end of a barrel, which may be what happened here. Guessing!

Joining the dots and could be wrong. All comments welcome!

Dave

It's true that we have no way to be certain of the conditions applying in the barrel when the damaging round was fired.

My comment about unburnt propellant was just to indicate a possibility, and maybe I should've said 'incompletely burnt'. One of the standard diagnostics in cartridge reloading for a charge that has failed to develop suitable pressure is smoke-streaks or sooty deposits on the case. Especially on the outside, as that denotes failed obturation. With normal-weight projectiles, the usual cause is an inadequate powder charge - but insufficient projectile mass would likely have a similar result.

If the wad (fibre or plastic?) remained in the barrel, it seems unlikely the round would've been deemed a satisfactory 'banger' - it would *usually* sound muted and pathetic. In fact there was a silent Soviet assassination pistol (described in the '80s IIRC) that retained the expanded propellant gas within the cartridge after using it to kick a captive piston into the tail-end of the bullet to expel it. So I don't know how seriously to take the 'attribution' to the remaining wad.

Got to break off for now, however interesting a discussion on outlier events in internal ballistics might get...

Edited By Mick B1 on 10/03/2020 13:04:05

Been reading this thread with interest. Just wondered why the OP hasn't considered using brass tube instead of paper for the home made cases. When I was a member of a wildfowling club many years ago one of the guys had an 8 bore gun. "Off the peg" cartridges for these hadn't been available in this bore for some time, but the owner had bought some 8 bore brass cases which could be reloaded many times.

Can't see that there would be a legal issue with the OP making pinfire cases, they don't become ammunition until they're capped and loaded by the end user.

I was surprised about the barrel failure with a home made blank. I produced a load of DIY 12 bore blanks for some poacher alarm mines by cutting round the inside of the crimp, pouring out the shot, filling the "cup" in the plaswad with tissue and waterproofing the cartridge with melted candle wax. I tried a few of these 2 1/2" cartridges in a 3" chambered 12 bore wildfowling gun before loading the rest of the blanks into my home made poacher mines. the gun barrel looked to be as clean as it would have been firing a "live" round.

Edited By Stueeee on 10/03/2020 21:35:25

They'd probably be better modified from all-brass drawn 16-gauge cases than from raw bar - that way you'd know the composition, hardness, ductility, annealing etc. were correct. It would need a bit of inventiveness to plug the c/f primer pocket and devise a way to decap and recap, and the shooter would have to be carrying out the reloading operation itself.

But I fully understand the OP's decision to ice the project.

I have a number of friends who use brass case for 8 bores, these were made from solid brass at some expense! The average wildfowler will not use many cartridges during the season and therefore the total number of cases required is low and reloading before each outing is feasible. The use of brass cases was discounted for a number of reasons 1) the number required, at least 50 2) if made from the solid 90% swarf 10% case 3) impossible to machine the boss/ cap recess in the cartridge base 4) finding tube to fit if soldering to the cartridge base. 5) paper cases look better with plastic cases a close second.. Robert Butler

Stueeee,

The fellow that blew up his gun was surprised, too! He was not expecting it, for certain. It could have seriosly injured him or worse. This was likely before plaswads were common. One common trick with 12 gauge cartridges was to pour in a small mount of melted wax and use them for ‘dismantling’ crow nests. Dad used home guard left-overs for that. Don’t know how they were loaded, but he would only fire them through his good gun - and only though the right barrel (less choke).

I used thousands upon thousands of kleena wads before even considering changing to plastic. Can’t remember the actual figures but I nearly always loaded with one over-powder wad, one half inch kleena and 1 1/4 ounces of lead (don’t think there was an under-shot card wad but certainly no over shot card). The heavier load required less powder than lighter loads and also the slower burning No. 62 nobel powder. It was cheaper to reload 1 1/4 oz than the usual 1 1/16 oz loads (which required more No 60 powder, two 3/8” kleena wads and probably an extra card wad).

As I recall, the barrel burst from somewhere about half way along and split backwards towards the breech but it remained mostly in one piece. He said he was lucky that he did not shoulder the gun or his hand could have copped it, It was a long time ago and the fellow will be dead by now - or well over a hundred! I bought my first shotgun from him and I got on well with his daughter when we visited (quite regularly).

SOD,

No snow in November - usually. This was in his back garden, next to his garage - not out in the field

Nobel shotgun powders burned at different rates depending on the pressure. They only burned explosively when under pressure. These would have been factory loads, not home reloads.

I used to have about 350g of powder in the reloader bottle, when full. No risk of an explosion if it ignited but it would likely have made a mess of me! A helpful turner made me some extra powder inserts twice - the first lot were in steel (so dumped!), even though I specified brass or aluminium. The reloader bar was aluminium sliding in a steel frame.🙂

I got slightly singed eyebrows, once, when demonstrating burning powder in an open bucket. There was quite a bit of powder and it was a lot faster burning than I expected. That was from eight bore ammunition but from an industrial weapon firing three ounce slugs as fast as they could be loaded. Was either Remington or Winchester ammo.

As a re-loader of ammunition for my centerfire rifles the problem of 'secondary ignition' is a known phenomenon that has destroyed a few rifles.

The recipe for disaster is to load a small amount of fast burning propellant into a cartridge case (maybe for subsonic velocity or just fire-forming the cases to a new calibre).

The current thinking is that if the propellant is unevenly distributed through the case (pointing the barrel down is bad news) then the primer ignition is sufficient to propel the projectile into the rifling where it jams until the primer flash ignites the propellant which then detonates due to the large surface area exposed to the flash.

With a projectile jammed into the rifling a pressure spike could result that could destroy a rifle.

Sorry that this was not related to shotguns but all I can say is 'Just be careful'

An alternative - or possibly supplementary - view is that the 'brisance' (shattering effect) of the primer breaks up the granules in low loading densities to increase the exposed surface area still further.

I was scared of this with my 'nitro for black' loadings in .577 Snider, despite the very well-regarded shotgun and pistol powder I was using, so I stuffed the unused airspace in the cartridge with polenta flour. Well, nobody else in the family would eat it...

Ref, the wad left in the barrel. I have had one instance of this in 25 years of shooting clays, shooting several thousand rounds per year. I was taught to ALWAYS check the barrels were clear before loading. In this cae it was the last pair of targets. The cartridge report didn't sound right and I missed the target! On checking te barrels, it was the clear that there was an obstruction. The wad was wedged pretty tight and took some shifting with a cleaning rod. This was potentially a highy dangerous, if I had loaded and fired another cartridge there could well have been a burst barrel. Good safety training and practice prevented this.

Edited By Stuart Bridger on 11/03/2020 16:40:44