"The 3in Ordnance Rifle" Topic

Of possible interest?

link

Amicalement
Armand

Good site with a lot of good information. Thanks for posting.

A votre service mon ami!. (smile)

Amicalement
Armand

The Ordnance rifle had a serious flaw, shared with all early rifled cannon. The spin from the rifling caused excessive spread of the case shot (aka canister). Since that was the primary anti-personnel round, it was a big problem and the main reason that the M1857 12-pdr (Napoleon) stayed in service during and after the ACW.

Be interested where you got that idea from.

The main issue with rifles was the damage canister did to the bore by chewing up the rifling.

In fact the initial Battery Holdings of canister for Rifled guns, per battery, in the AoP at Gettysburg, was 24 rounds higher than the Napoleons.

The main difference in canister performance was the 1.62in size difference in the two guns bore which gave the Napoleon a better spread.

Hanging on to them was also due to the South's manufacturing capabilities which made smoothbores and their ammo easier to make. Not to mention captured ones easier to reuse.

The South had further ammo problems with rifled guns as the 10 Pounder Parrott, as first produced, had a smaller bore than the 3in Rifle. Leading to interchangeability issues. The Union solved this by reboreing its Parrotts but the South's lack of machine shops kept this as a problem.

The longer range of rifles didn't always make a difference – its no use if God's put a hill in the way – but if there were good sight lines Napoleons suffered in counter battery fire due to the greater accuracy of their opponents. As did troop formations under shell fire where the airburst could be more effectively positioned

At canister range the bigger bang from Napoleons was undoubtedly the winner.

YouTube link

Trajanus, that "idea" came directly from official tests on rifled artillery in a number of different armies – US, British, Prussian, French, Austrian among others. The gist of them is that the opening angle of canister for a smoothbore gun was on the order of 5 degrees, while that for a rifle was anywhere from 10 to 15 degrees, depending on the pitch of the rifling. That means that at 100 yards, the impact circle of smoothbore canister was 8.7 yards in diameter, while that of the rifle was anywhere from 17.4 to 25.9 yards. Thus the balls from the rifle were spread over four to nine times the area, most of which had no troops in it.

The bore diameter made no difference in the spread, the opening angle was the same for 6-pdrs, 12-pdrs and even 32-pdrs. Bore length had some effect, but not much. It was the centripetal force of the spinning projectile that caused the increase.

That's interesting.

Is that also related to the bursting point of the tin?

The Napoleon had a higher muzzle velocity than the 3in so one assumes the container was moving faster at that point but from a Rifle it would presumably have been spinning when it opened, so was it that scattered the contents more?

I think this could be supported by the opening angle being the same regardless of bore of the piece.

Its also interesting that as far as the Civil War was concerned Rifles continued to increase in use.

Henry Hunt was concerned about the number of 12pdrs available during the Gettysburg campaign but all bar two of the Artillery Brigades still had two or three Batteries of Napoleons. The big exception being the Calvary which had none at all due to the 3in Rifle's weight advantage.

Do you know the dates of these tests? It would be interesting to compare them with the introduction of Rifles in the various armies and what combat deployments took place before and after them.

Why would the canister follow the rifling? Was it that tight a fit?

Any black powder weapon needed a tight fit to maximize the gas pressure from the charge and in the case of smoothbores, minimise the "windage", the gap between the wall and projectile that allowed moving from side as it shoots up the barrel.

The Minie ball achieved this and spin, by expanding the base into the rifle's groves which improved performance over smoothbores and the old round ball rifle's.

Artillery rounds of all kinds in the Civil War were mounted on wooden sabots for the same reasons, reducing gas escape in general and picking up the twist when fired in rifles.

The thing that puzzles me is the often repeated (I do it too) statement that canister damaged the rifling, when last time I looked, iron was harder than wood or tin!

Thanks!.

Amicalement
Armand

According to Arms and Equipment of the Civil War by Jack Coggins, most of the shot and shell (not canister) for rifled artillery used brass, copper, lead or wrought iron cups (at the rear) or bands (along the sides) to take the rifling. No mention of wood, which he does say was used for smoothbore ammo.

Ammunition in smoothbore cannons did not seal completely, they left a small gap which is referred to as "windage". For a rifled weapon, it had to seal at least enough to grip the rifling.

I too, have read that firing canister out of rifles was problematic -- that it affected the spread and made it less effective. However, it's been a while since I studied that, and I do know that special canister rounds were developed for rifles during the war.

Artillery reenactors explained to me that the ideal situation when firing canister is to have hard ground and to "bounce" the canister off the ground before hitting the target. This had the effect of "flattening" the dispersion and helped get more hits.

You can see that in the live fire video I posted the link too above.

Don,

Managed to find my copy of Coggins! One of the first Civil War books I owned. First Published in 1962, gasp!

I think I got it a few years later. I was in Junior High in 1962!

I was amazed to find out it was reprinted in 1983 and 2004 by other publishers.

Saw the parts you referred to. Its interesting that there's no illustration of canister for rifles. Maybe it was too similar in appearance to the Smoothbore equivalent. Which as you say he mentions being nailed to a wooden sabot.

As you will have seen rifle projectiles were often quite distinct in appearance – people kept trying to build the batter mousetrap – but when it comes down to it canister was well, kind of can shaped!

On the subject of canister fire, it is worth keeping in mind that, quite part from rotation imparted to the canister round by the rifling, the bore of a rifled fieldpiece was only 2.9 to 3.0 inches, while the bore of a 12-pounder was 4.62 inches. BIG difference, there alone.

I also wonder what the MV of canister fired from a rifled gun was in comparison to that fired from a smoothbore. The normally credited MV of a rifled gun was about 1100 fps while that of a smoothbore was about 1400 fps.

Just sayin'

B

Well that's what I had always assumed but see "rmaker" post from 18 Nov above for a different perspective.

Hi Trajanus,
My post definitely could have been clearer. I fully support rmaker's commentary re the differences in cones of dispersion. And I do subscribe to the cause being rotation of the canister tin imparted in the bore by the rifling.

I was intending to raise two points -

> The MV of a smoothbore canister round was PROBABLY higher than that of canister fired from a rifled gun (need to check my reference books).

> For an equal round weight a 12lbr smoothbore canister round was a relatively wider and shorter round, while the canister round fired from a rifled gun of considerably smaller bore was comparatively much longer in comparison to its diameter.

B

Ah! Right!

I was going to check the MV too, still haven't got to it!

I see where you are coming from with the canister round shape. Were the ball diameter and quantity's not different too? Another thing too look up!

Hi Trajanus,

Managed to dig up some partial information from the book "Field Artillery Projectiles of the Civil War 1861-1865" by Kerksis and Dickey:

Charge for a smoothbore 12-lbr gun = 27 x iron balls, each of approx. 1.5-inch diameter.

Charge for a 3-inch rifled gun = 37-39 x iron balls of approx. 0.90-inch diameter

B

Yeah, that fits with what I found.

As does the MV you quoted. Well to be absolutely truthful the 3in came in at around 1250, I think, but the point stands.

This mirrors the infantry position as I recall, where I the smoothbore musket actually has a higher MV than the rifle musket.

Hi Trajanus,
Another interesting bit that I found in the Kerksis and Dickey volume was that case shot fire from rifled artillery suffered similar lateral dispersion characteristics due to the spin of the projectile.

The devil is always in the details ….. ;-)

B

How the hell did they work that out ?

I assume that must refer to when it was use as a canister substitute – zero elevation and fuse cut/set to explode the round immediately after leaving the tube?

Can't get my head round a comparison test on an air burst at 700 yards!

canister IS case shot!

Nope, there's two types of air burst ammunition.

Originally called Common Shell and Spherical Case both explode with a bursting charge set off by a fuse. The former explodes into fragments like a grenade the latter does that too but contains musket ball size sub munitions which scatter like a shotgun blast from above.

During the war as rifle projectiles became common their names got shortened to Shell & Case and quite often one name served for the other in reports. If you were on the receiving end, what it really was didn't matter too much.

Case was often referred to as Shrapnel after the British guy who invented it in the Napoleonic period. That name came back into fashion in WW1 when it got used for any chunks of flying metal coming from above, of which there was one hell of a lot!

The content of case was what allowed it to be used as a canister substitute when the real deal ran out. Set with a zero timed fuse it sprayed out in a similar manner but wasn't as good. There is no fuse in canister the tin bursts on leaving the tube due to differential air pressure.

When used in this way Case was often referred too as "rotten shot".

From the Civil War Dictionary by Mark Mayo Boatner III, revised edition (p. 131):

CASE SHOT. The three principal kinds of case shot were Grape, Canister, and Shrapnel (or spherical case shot), according to Benton's West Point textbook of the period. "Case shot" is sometimes used synonymously with "canister," however, and may even refer to "shrapnel." Roberts, the other standard reference, uses the terms "case shot" and "shrapnel" synonymously. The reader must therefore be on guard and interpret the meaning of "case shot" in terms of context and the accuracy of his source."

Don,

That's interesting. The fact it doesn't concur with manuals in use at the start of the War and during it even more so!

There's a whole bunch of them on this site. Sorry I can't copy and paste the relevant parts but they are all in pdf format.

If you scroll down to Page 90/91 on this one, for example, you will see the differences.

PDF link