Early armor piercing ammo?

[Leslie Sapp]

I saw this report on some iron cored lead shot found on the Mary Rose wreck. http://www.telegraph.co.uk/earth/environment/archaeology/9991936/Mary-Rose-reveals-armour-piercing-cannonball-secret.html
The speculation in the report was that it may have been an early form of armor piercing shot.

What say you, Gentlemen and and Ladies?

[wch]

What was the cost and difficulty of mining and refining iron ore as opposed to the cost of adding to the weight of the projectile with lead?
Could the lead coating have been a method of preventing the corrosion of the iron projectile by salt water and sea air?
Maybe the lead coating was used to make the projectile more spherical in shape, thus more accurate?

[Leslie Sapp]

Corrosion resistance is certainly a possibility. They may also have been taking advantage of the malleability of the lead, maybe even counting on some obuteration in a tight bore. I wonder what the diameter of the bore it was to be shot from was.

[Bigslug]

Could the lead coating have been a method of preventing the corrosion of the iron projectile by salt water and sea air?
Maybe the lead coating was easier to make the projectile more spherical in shape, thus more accurate?

Could be both, but I tend to agree more with the latter. This was pretty early on in the era of metallic cannonballs. Pretty early on in the period of working large chunks of iron, really. Sure, there were blades, horseshoes, and the like, but blast-furnacing iron to a liquid, castable state in the amounts needed to feed a whole shipload of cannons was still pretty new stuff. Getting the cannonballs cast round enough would have been a trick at the time, and then there's the issue of getting the diameter consistent enough to be used randomly in multiple guns.

Henry VIII was a long time before the refinements seen in the Napoleonic wars.

[10-x]

When was the 1st truly armored vessel, IIRC it was the CS Virginia?

[wch]

Apparently the French Navy used ironclads in the Crimean War of the 1850's, so they would predate the CS Virginia.

[waksupi]

Interesting projectiles. Apparently the Mary Rose had quite an arsenal aboard. I have four musket flints from the Mary Rose here.

[longbow]

First I have heard of lead clad iron cannonballs though I am no expert.

My understanding is that early iron cannonballs were cast iron not wrought iron but after searching the internet for what I thought would be an easy answer, I came up with little information so far. Both are mentioned but I did not find mention of solid lead or lead clad iron round shot for cannons except in the link posted in the OP.

If cast iron then the problem of handling a large chunk of wrought iron would not be an issue though it certainly was for making large wrought iron pieces... a man had to be able to handle it for forming. No big machines available to do the work in those days. It was a man with a hammer.

Cast iron is very fluid and will take intricate shapes in moulds easily so casting a smooth, accurate sphere would not be hard at all and much quicker than a making wrought iron ball would be so my vote goes to cast iron balls. My opinion of course.

Also, I can't see how a lead coated iron cannon ball would be any better at penetration (in a wooden ship hull anyway) than solid lead especially hard lead. The lead may have been added for mass but a solid lead ball would be even heavier so... why an iron core?

Cost ~ maybe one was cheaper than the other but which? Lead was commonly used for grape shot and musket balls, and cast and wrought iron were everywhere from the cannon barrels to iron fittings and barrels on muskets, cooking implements, etc. and most information I found shows iron cannon balls in later years and stone in early years.

I would have thought that lead would be cheaper and easier to cast but then why do most cannonballs seem to be iron?

Anyway, all speculation on my part but an interesting issue that I thought would have a pretty easy answer.

I hope someone that knows will post because now I want to know!

Longbow

[justing]

very cool

[MtGun44]

Very likely corrosion protection and increase in accy thru closer bore fit.
It was a common sailor's job in the old days to chip the corrosion off of cannonballs, kinda
like chipping paint and repainting in the modern Navy. Necessary as heck, but not
any fun. Rusted and chipped balls could be pretty much undersized and poor bore
fit would not help accy.

Bill

[Leslie Sapp]

The more I think about it, the "armor piercing" theory may be right. If you think about it, this not a whole lot different from a modern steel core projectile or a sabot tank round. If it was at a sufficient velocity, the lead would spatter against the hull, but the iron core would continue on.

[longbow]

But a solid iron ball would have higher velocity so would probably penetrate better.

The comment in the article is: “We found there were small iron cores inside..." The small cores would not likely penetrate as well as a full size iron ball, especially since a lot of energy would be wasted in peeling the thick lead off the core.

Also, modern armour piercing projectiles using a hardened core are shaped and use the outer mass to help drive the core through. A ball would not work like that.

Maybe a bit different if the iron core was large and just thin lead to provide closer bore fit, corrosion resistance or whatever. Still, it was early days and maybe they were experimenting.

[runfiverun]

I think the lead would have just protected the iron balls from salt water corrosion.
it would have been nothing more than a sheet of lead wrapped and worked around the balls.
once the lead oxidized it would have been the end of the corrosion.
a coat of paint could have been added [shrug]

[MtGun44]

I get the impression that some think that lead was the norm and the unusual thing
was the iron cores. The lead coating is the unusual thing. Cannon balls were iron in
those days.

No armor but the hulls of some ships were very thick laminated oak. US 44 gun frigates,
like Constitution (Old Ironsides) were particularly good at bouncing smaller cannonballs
off with minimal damage, which is, of course, where the name came from. IIRC, they used
live oak in crossed layers. We changed the whole of naval design with these three ships,
they really kicked butt in their day.

Bill

[MUSTANG]

The case for corrosion resistance makes the best argument for me. Having put in a bit of time at Sea during my military career, I have seen just how fast iron (steel) can rust in salt spray environments. The most compelling reason though, goes back to the Roman practice of coating iron security bars and structural bars in stone construction with lead to prevent corrosion. The use on Cannon Balls would simply be a new application of a very old technology.

Mustang

[wch]

The more I think about it, the "armor piercing" theory may be right. If you think about it, this not a whole lot different from a modern steel core projectile or a sabot tank round. If it was at a sufficient velocity, the lead would spatter against the hull, but the iron core would continue on.

But these projectiles are unique, i.e. there is no evidence to support an AP theory or the Royal Navy (not to mention the French, Swedes, Spanish, or Netherlands Navies) would surely have picked up on the technique.

[Bigslug]

But a solid iron ball would have higher velocity so would probably penetrate better.

The comment in the article is: “We found there were small iron cores inside..." The small cores would not likely penetrate as well as a full size iron ball, especially since a lot of energy would be wasted in peeling the thick lead off the core.

Also, modern armour piercing projectiles using a hardened core are shaped and use the outer mass to help drive the core through. A ball would not work like that.

Maybe a bit different if the iron core was large and just thin lead to provide closer bore fit, corrosion resistance or whatever. Still, it was early days and maybe they were experimenting.

THIS

Keep in mind that the FBI took until 1987 to really take a scientific look at wound ballistics and until 1993 to get their findings into the standardized "six barricades" test protocol we have today. All this stuff that we "know", we haven't known all that long.

The guys on the Mary Rose lived in the age when thought they had valid, legitimate reasons for shooting their Christian enemies with round bullets and the non-Christian ones with square. A lot of these folks might have thought that steel would be better for penetration solely because of hardness, but may have failed to grasp the whole momentum issue that lead brings to the party.

In short, whatever their reasons for wrapping a steel cube in lead, they may not necessarily have been correct.

[mpmarty]

They covered them in lead so they would stack easily on brass monkeys.

[MUSTANG]

They covered them in lead so they would stack easily on brass monkeys.


Hence the old saying in an extreme cold weather environment:

"Cold enough to freeze the balls off a Brass Monkey".

(Seriously, that is where the phrase originated)

Mustang

[longbow]

The article says these cannonballs had small iron cores. It doesn't say they had lead sheet wrapped around them.

Since pretty much all other cannon balls seem to have been iron at the time and after, they must not have accomplished whatever purpose they had.

Solid lead would be heavier and have lower velocity and higher trajectory.

Solid iron would be lighter and have higher velocity and lower trajectory.

Soft lead would flatten out and impede penetration.

Hardened lead alloy should have about the same penetration in wood as iron.

Maybe the goal was to reduce the weight from solid lead and gain some velocity.

All speculation unless some historian has seen this before and knows why they were made that way. So far I find no other references to lead clad iron cannonballs.

Longbow