Civil War Gunboat vs Armor P 50 cal Q

Silly question, but one I have been thinking about for some time. Scenario - you can travel back in time with a 50 cal sniper rifle and all the ammo you can carry. You want to stop the North gunboats from coming down the Mississippi during the battle of Vickburg. Would one 50 caliber rifle with armor piercing shells be able to stop a Civil War ironclad, shooting it from the banks of the Miss? Supposing you are a very good shot, and you can carry any type of 50 cal shell (not just armor piercing). Also, I have read the ironclads had 2 inches of iron back up with 2 feet of wood as protection.

I think you’d have about as much luck as trying to sink a battleship with an antitank missile.

While the rifle could probably penetrate the armor, you’d still have to have pretty good shot placement to put the thing out of action.

You’d probably have better success trying to fire into the vision slits, and popping anyone who stuck their head out to get a better look.

It would seem a modern day armor piercing 50 cal bullet would go through both sides of the ironclad, and go through just about anything on it?

You might want to consider something like the Mark 211 .50 ammunition, AKA "Raufoss ammo.’ With a PETN or RDX core, it’s supposed to have the rough destructive power of a generic 20mm shell. As far as penetrating armor goes, from the global security link, here is a comparison between the Mk 211 (Tracer and non-Tracer) and AP-S NM173 (armor-piercing sabot?)

Not sure if Armour = Rolled Homogeneous Armor, but I am guessing it’s much tougher than Civil War era iron. (Aside, would that have been pig or cast iron? I don’t think they had even basic steel back then.) 2 inches of iron ~ 50mm, so you’ll want to be close, whichever ammunition you end up using.

A video of someone putting Mk-211 ammo through a 50-Caliber, M82 at various stuff may be found here. Your guess is as good as mine as to its authenticity. The linked video, at about 3:30 purports to show a hole through 1 inch RHA, made by a SLAP round from the M82. The range isn’t specified. The sound and video aren’t synced very well, but you can kinda get an idea as they shoot manhole covers, rail brackets, cinder blocks, things like that.

Well, you’re on the Mississippi river. The ship can be a mile or more away from you. That’s going to reduce your armor piercing potential. The armor on the ironclads was designed to deflect cannonballs weighing 12-24 pounds and traveling at high velocities. You might pierce it with an armor piercing round, but how much energy will the projectile have left to do any damage?

The ironclads were steam ships, probably paddle wheelers. Your best bet would be to hit a boiler. Don’t know how heavily those were shielded. (I’d surround them with the coal bunkers if I was designing the ship.) And that involves some fairly accurate shooting which would be difficult because (one assumes), the ships would quickly be returning fire with black powder weapons which means that they’d be largely concealed behind a bank of smoke.
Question about the OP – did you literally mean all the ammo you can carry, or did you mean “unlimited ammo”. Because a 50 cal bullet, if I’m reading the Wiki page correctly, weighs up to 700 grams or 1.5 pounds. If you’re limited to all you can carry, that’s probably about 50 rounds.

Those Raufoss rounds could conceivably do the trick – the Civil War ironclads were converted wooden boats. So if the incendiaries get through the armor and they don’t have good fire control, it could be game over.

700 grains=1.6 oz.

Ah, thanks.

According to this website , trying to make sense of the numbers tossed about (1 inch = 25.4mm):

11.9 inches Krupp Cemented armor= 13 inches of Harveyized = 15.5 inches nickel steel = 20.1 inches steel = 25.4 inches iron.

Sooo… an ironclad with 4 inches (101.6mm) of iron is the equivalent of 3.2 inches (81mm) of (mild?) steel.

I tried looking at the wikipedia page on SAE steel grades, but I can’t translate much of that to armor protection equivalents:

The Virginia had four inches of iron armor over 24 inches of layered oak and pine - this was angled to deflect shots away. Even if a projectile were to deform the metal the layers of wood would splinter and absorb much of the impact.

2x2 inch iron armor, not 4 solid inches. I would think that would be even more effective in defeating the .50 round.

When I get home and have access to my library, I’ll see if I can look up the specs on the Union ironclads used during the Mississippi Campaign.

Less, according to the old site I linked to. Quoting paragraph 1202, with my added bolding:

I just noticed, for full disclosure, it appears that this paper may have been written in 1925 (!):

from what i read, the civil war ironclads typically had 2 inches CAST iron (if that makes a diff). also, i believe most shots would be at 3 fourths mile. and only the ammo I could carry. bear in mind that i would be in modern protective gear with state of the art helmet etc and ultra modern scope on rifle. I mean if i can afford to build a time machine, I am going back with the best.

I thought that the boilers on riverboat ironclads, being above the waterline by necessity of shallow draft, were vulnerable to enemy fire and would explode if pierced.

So, to sum up:

  1. I personally am very well protected, in the latest body armor available - from head to toe.
  2. Best vision scope with Raufoss ammo.
  3. Can probably have 500 rounds with me.
  4. I will assume the ironclad will be within 3 fourths a mile, maybe one half.

Is it the majority opinion that I will be able to take out an ironclad? And possibly more than one if “they keep coming”?

Riverboat ironclads were refered to as tinclads, in part due to the very thin armor used.

They were used as mobile artillery platforms, & troop/cargo transports.

Note–some supplimented their metal armor with sandbags.

Civil War era steam boilers were notoriously tempermental, had few if any safety features, & often exploded all on their own.
Note the Sultana Explosion.

Your .50 round might do quite well, although I’d prefer a 20mm antitank rifle, myself. HE rounds, please.

But that’s just the bullet weight. The entire cartridge - bullet + case + powder + primer - is significantly heavier. According to this page, “the weight of 100 rounds of linked M2 ball in ammunition can is approximately 35 pounds”. So dump the can & the links, and you’re probably talking 0.3 lb/round. So your 500 rounds would weigh 150 lb.

Civil war armor was of poor quality. Imagine railroad rails rolled flat, common steel. On the other hand, the armored layer was often backed by a conventional boat, with all the wood that implies.

Since that era, steel armor has gone through at least three improvements, face-hardening, increased carbon and then something else. So I figure you most likely could defeat CW era armor with a modern round.

But stopping a ship is another thing altogether. These guys were working in a dangerous environment, live steam, grody ergonomics and flying spall all added to the fun. Would a couple of bullets even be noticed?

On the Cairo, an Eads City-class ironclad on display at Vicksburg, the boilers are below the waterline.