Soft metal barrels for target rifles

[bones92]

So I finally started reading Walter Cline's "Muzzle-loading Rifles - Then and Now"

First, I'm very much enjoying what I'm reading so far, and wish I'd bought this book a couple years ago.

Second, the book describes soft iron barrels being preferred for target match shooting.  He describes how some gunmakers would temper the barrel by covering in wood, burning the wood and letting the fire die down till it's cooled.

I'm trying to figure out why a soft metal barrel would be preferred.  Wouldn't the rifling wear out faster over time?  Wouldn't it be more subject to whipping motion during firing (as opposed to a hardened barrel, which I would assume is a bit stiffer)?

[EC121]

The soft metal doesn't resonate or vibrate.  Does lead ring when you hit it?  The heating also relieves the manufacturing stresses in the metal.  Point of impact is more stable when the barrel heats up.

[bones92]

Ok, that does make sense.  I knew there had to be a reason or two... I just couldn't think of what it might be.

Curious to know if they ever hardened the bore surface a bit, for longer barrel life.

[WadePatton]

Ok, that does make sense.  I knew there had to be a reason or two... I just couldn't think of what it might be.

Curious to know if they ever hardened the bore surface a bit, for longer barrel life.

As far as I'm educated, lead doesn't wear steel.  Rods kill bores, not balls. 

[Dphariss]

The soft barrel steel/hard barrel steel thing is a tempest in a teapot. The steel has to be UNIFORM temper from end to end for best results. Nor are  barrel steels "hard". 4140-4150 are much harder to cut smoothly than some steels but they are not really "hard". Button rifled barrels need to be normalized after rifling to prevent changes in bore dimensions when tapered due the high stress the process puts on a barrel blank.
 ALL steel will set up some vibration or harmonic due to the pressures and the rapid rise of pressures in the firing cycle. Hang a barrel vertically by a wire and tap it with small hammer or piece of metal. Its not going to produce a dull "thud" like a chunk of lead. Almost all steels are harder than pure iron but even most iron has some carbon content. In modern terms 1008 is iron 1010 is steel. I suspect that back in the day that anything that would not harden when quenched was thought to be iron.

Dan

[Dphariss]

"Naked" lead bullets that are CLEAN and lubed with clean lube will cause virtually no wear. However, cloth or paper patches can cause some barrel wear and the powder gases can be erosive in some cases, especially in Iron barrels or so I have been told. Dirty patches, paper or otherwise will increase wear.

Dan

[Daryl]

I would suspect that loose ball and patch loads that do NOT seal the powder gasses behind the ball, would suffer the flame and gas erosion more than a gun always shot with tight combinations.

We know that gas erosion is a huge wear factor in modern rifles with 4140 AND 4150 barrels, even though it is contained behind the bullets.

I suspect weak combinations of ball and patches in the softer steels of our muzzleloading barrels, especially those of 12L14, might suffer even more from this erosive force.