Barrel rupture

[Mad Monk]

Well, that's interesting, Bill. I remember hearing about those chrome lined barrels
& wondered how they worked, or didn't.

The cure for chrome flaking came out of the Canadian military.  In Canada a company came up with a mixture of chrome and nickel.  Applied in the bore as a powder clinging in a thin film to the bore metal and then melting it with a plasma  "flame".  This, in modern military weapons.

Bill K.

[Mad Monk]

Thank you for that info , Bill.  I too believe that the goings on re a short started ball are similar to "water hammer"
I've seen 10 inch and even larger butterfly valves with banana like disc /shafts from water hammer.  I've also seen elbows [pipe] blown off.   That said, the vent in a flint barrel acts as a pressure relief , although not quickly enough to prevent bulging in some but not all cases.  One fellow at our club got away with many many " short starts"  until one day fate did not favour, and the barrel bulged .   I wonder if this was a case of fatigue in terms of the barrel material ?

Something just clicked in my mind.  When I was forced to switch over to those evil nipple guns in my powder testing I started to drill a single small hole in the nipples that would then be covered by the cap.  To see if that would mimic the vent in a flinter preventing any "water hammer" in the gases in the bore.  When I ran that thought past my buddy in Australia he came back with a bunch of photos of some of his antique English sporting arms showing the tiny holes in nipples or in the bolster holding the nipple.

I had noticed in my historical reading that the switch from flinters to percussion saw the numbers of failed barrels jump up.  And the papers of Nobel and Abel in England in the 1860s and 1870s go into what goes on in the gases in the gun bore where a "projectile is materially removed from the powder".   They describe the movement of the gases sloshing back and forth in the bore like water in a bath tub.  And that can result in very high pressures in narrow bands in the bore.

Bill K.

[coupe]

Hot shot nipples have such a hole in the side under the cap, it opens up the side of the used cap when fired. I always thought it was to help remove the spent cap on a tight nipple, maybe it was to relieve the pressure wave developed. I've had one on my .54 since it was built, about 3000 shots through it now. 

[Daryl]

I tested a hot-shot nipple on my .69. It did allow reloading without removing the spent cap, however it also opened up the groups a bit, over a standard nipple.
I doubt adding more powder would have improved the accuracy as the gun has a wide range of loads that give virtually identical accuracy, but, you never know
unless you try. I didn't as I just quit 'testing' the hot-shot nipples. Still have a couple in the small tool 'kit' bag.
Lifting the hammer to 1/2 bent position is absolutely necessary when reloading this rifle, as the patched ball will ride back up the bore if the compressed air is not
allowed to escape at the nipple as the ball is shoved down. If I forget, the patched ball simply stops before getting to the bottom and as I relieve pressure on the
rod, the ball pushes the rod back up the bore. I bend over, pushing the hammer back to 1/2 bent and peshewww, out comes the compressed air as the spent cap
is pushed off the nipple - I then re-seat the ball on the powder and done.

[D. Taylor Sapergia]

My Joseph Lang .66 cal rifle has a vent in the side of the platinum plug on the breech plug.  After a session of shooting, there is a small amount of fouling around the vent, so it does allow gas to expel.  Out of habit, though, I still lift the hammer off the nipple,, and remove what's left of the cap.

[Old Ford2]

 The short started ball was still in the barrel.
[/quote]
Well at least you would have a ball to shoot in the next gun. It wasn't a complete loss.
I am an optimistic .
Seriously, many of us don't check for a loose ball after a long walk or climbing, jumping as a hunt may demand.
I once had a Pedersoli double .58 that the second barrel would let the .58 minie ball creep forward. After going to patched round ball in the same gun eliminated the issue.
Many times the minie bullet would creep three or four inches up the barrel.
Fred

[Daryl]

The short started ball was still in the barrel.

Well at least you would have a ball to shoot in the next gun. It wasn't a complete loss.
I am an optimistic .
Seriously, many of us don't check for a loose ball after a long walk or climbing, jumping as a hunt may demand.
I once had a Pedersoli double .58 that the second barrel would let the .58 minie ball creep forward. After going to patched round ball in the same gun eliminated the issue.
Many times the minie bullet would creep three or four inches up the barrel.
Fred
[/quote]

Fred - that is just one reason why, in the 1800's, slugs did not gain a foothold in 'double' hunting guns, until the ctg. era, in fixed ammo.
They could not be trusted to stay put on the charge in  either of the barrels, nor the left barrel after the right was fired.