KABOOM through SEE, what truth lies in this?

[Larry Gibson]

Outpost75

Not being an artillery guy I've no 1st hand experience with S.E.E. in artillery rounds. However, I have read and studied the matter in conjunction with the S.E.E. phenomenon in firearm cartridges. Much of the criteria for such to occur in either is the same with the exception of the initial ignition stage. In the artillery rounds, as you mention, the initial cause seems to be the "black powder igniter contained within the booster or flash tube being fractured, causing delayed ignition". In the firearm cartridge the delayed ignition is caused by primer "flash" not igniting the powder (usually a slow burning powder with heavy deterrent coating to control the burn rate) sufficiently that the powder begins burning progressively. The primer "flash" ignites the powder just sufficiently that is "smolders" so to speak while the force of the primer flash pushes the bullet into the chamber throat where it momentarily stops or sticks. The powder then starts to burn and the pressure rises to a catastrophic level before the bullet can move quick enough the decrease pressure via the expansion ratio. Note in most S.E.E. events the bullets do exit the muzzle. They just don't do it quick enough and something else gives.

As to "high pressure excursion" perhaps the technicians at Hodgdon changed the definition to fit, I don't know. They should however, as tomme boy mentions, be very familiar with S.E.E. because the earliest reports are most notable from the early '50s with the use of H4831 in 25-06 and other "over-bore" cartridges. I have found several probably S.E.E events occurring prior to that in some writings including Hatcher's or Whelen's. The phenomenon just wasn't recognized as such back then.

[robg]

the blow ups ive seen have been caused by underloads then a full load hitting the bullet stuck in the barrel .one idiot managed to fire 7 rounds in his 44mag .he had fired 6 then the seventh jammed the cylinder ,now that takes a special kind of idiot.the barrel with the side cut off was on display as a warning to others.

[Larry Gibson]

"the blow ups ive seen have been caused by underloads then a full load hitting the bullet stuck in the barrel"

A bore obstruction but of a slightly different nature than occurs in an S.E.E. In an S.E.E. the bullet itself when it stops moving and is stuck in a probable fouled and/or rough throat becomes the "bore obstruction". Essentially the end result from both is the same.

[john.k]

Some years ago ...30-35?....one of the gun mags did blowup tests on some of the popular , modern bolts ......firing them with barrels full of sand .Standard factory load ammo.......Dont recall any of them "blew up" ,and a couple were still operable when cleared and cleaned ...others had the bolts jammed .....So an obstruction doesnt seem to cause a kaboom in a "3 rings of steel" type gun.......Every military force did tests with lodged bullets ,and the results are well known.

[303Guy]

Now that you mention it, Springfield armory did some trials with the Springfield 30-06, firing them unerwater with the barrel flooded. The bullet exited and actually pieced the side of the tank. Mythbusters did something similar and so have others. If a barrel full of water does not destroy the gun then why should a bullet lodged in the throat? Not lodged in the bore - that would bulge the barrel. Also, snow plugging the muzzle does interesting things.





That last one being a breach obstruction.

When I was thinking of a double bullet, I had a bullet dislodged from the case with no powder charge and the next round having the bullet pushed back into the case, reducing case volume and doubling the projectile weight. Would that be something like that last pic?

But how is that different from a bore full of water?

I was once told of an incident in which a 270 cartridge was chambered in a 308 rifle. This was in a gun factory and in a test rig. The action gave way, the receiver ring splitting open. The barrel landed halfway down range (short range - the gun was remotely fired). The barrel itself was undamaged and the bolt held.

[15meter]

I was once told of an incident in which a 270 cartridge was chambered in a 308 rifle. This was in a gun factory and in a test rig. The action gave way, the receiver ring splitting open. The barrel landed halfway down range (short range - the gun was remotely fired). The barrel itself was undamaged and the bolt held.

270 in a 308, will that chamber? Haven't tried it, just picturing the two rounds in my head and not sure that would work.

But I've been wrong before, just ask my mother-in-law.

About anything.

[Larry Gibson]

"But how is that different from a bore full of water?"

Different because the rifles were also completely submerged. The exterior pressure was equalized. Much different if just the bore is full of water with just atmospheric pressure on the outside. During SF water operations we had to be very careful the water had drained from the M16 barrels before any live fire. The plastic muzzle caps (actually an issue item) were used as the just blow off from the compressed air in front of the bullet. Or, we used electrician black plastic tape to seal the muzzle which also easily blew off. With 30 cal or larger the water drains out easily but with the small 5.56 bore the viscosity of the water many times made it not drain easily. If the water was not drained out when you come up out of the water and shoot you can end up with barrels as pictured in the post above.

[john.k]

That would be a 308 fired in a 270 chamber ......and 303guys #1 pic is a scope collimator spud left in the bore (for safekeeping?)

[15meter]

the blow ups ive seen have been caused by underloads then a full load hitting the bullet stuck in the barrel .one idiot managed to fire 7 rounds in his 44mag .he had fired 6 then the seventh jammed the cylinder ,now that takes a special kind of idiot.the barrel with the side cut off was on display as a warning to others.

Not necessarily an idiot, I had a friend do this with a revolver in competition, one of those run and gun things where you are banging away a reactive targets as fast as you can.

He said recoil was not noticeably different, at least not while shooting in competition. He was just surprised he missed as many targets as he had, had no idea there was a problem until the cylinder locked up.

Having shot cowboy action, I can see this happening pretty easily.

[swheeler]

I would have to go with Hodgdon on this one

[303Guy]

270 in a 308, will that chamber? Haven't tried it, just picturing the two rounds in my head and not sure that would work.

But I've been wrong before, just ask my mother-in-law.

About anything.

I said that the wrong way round. 308 in a 270 chamber. The 308 bullet headspaces on the 270 chamber neck area. Sometimes it just swages the bullet down and gives stiff recoil.

The way those barrels split open tells us something about how they were made. Not a solid rod bored down the middle.

[swheeler]

I said that the wrong way round. 308 in a 270 chamber. The 308 bullet headspaces on the 270 chamber neck area. Sometimes it just swages the bullet down and gives stiff recoil.

The way those barrels split open tells us something about how they were made. Not a solid rod bored down the middle.

303 I'll bet they are a solid rod bored down the middle. It looks like the splits follow the rifling on the first, maybe the fluting on second and the chamber just let go in one place, that's what I see?

[303Guy]

303 I'll bet they are a solid rod bored down the middle. It looks like the splits follow the rifling on the first, maybe the fluting on second and the chamber just let go in one place, that's what I see?

You're right. Split along the flutes.

I do believe that some barrels were made by folding a flat bar into a welded seam tube with a small ID. This may have been in the early days or something.

That first pic does not appear to be fluted and I've seen a clearer photo of a barrel split like that, allegedly from having a plug of snow in the muzzle which makes sense since the guy was hunting in the snow. It was a stainless steel barrel and looked suspiciously like it split down weld seams. Very straight splits and very even segments. I don't know - I shall see if I can find out anything.

[Chev. William]

Damascus Type barrels were all hammer welded Steel and Iron strips.

I wonder if the tri-split barrel might have been hammer forged around a mandrel?

Chev. William

[john.k]

There are some pics of split barrels on new Tikka rifles on the net.........all steels can have flaws ,and generally careful checks find the faulty blanks ......Ive read that Spanish Mauser barrel blanks were hydraulically tested at very high pressures before any machining was done ,to avoid wasted operations .