"Smoothbore" is pretty self-explanatory. Of note is the wear within the bronze barrel. This wear or "windage" (that's right, it had nothing to do with wind) forced the gunner to have to be very aware of the idiosyncrasies of the barrel and the influence of the windage upon the shot.
And here is the gaping maw of the big brother to the six-pounder; the twelve pound light gun howitzer. A heavy, versatile, and feared piece of artillery.
The muzzle of a three-inch Parrot gun. This cast iron tube was very accurate, very cheap to produce, and very brittle. These guns often burst, doing more mayhem to the gun crew than to the enemy.
This shot down the tube of the Parrot show the three "lands and grooves" of this system, as well as the ubiquitous bird's nest.
The still, very crisp, rifling. Clearly this gun saw less action owing to its late entry in the conflict.
This is the Confederate manufactured version of the "Napoleon". Unlike the union version which has a pronounced muzzle swell, the Confederate copy deleted that swell as an economy move, that's merely extra bronze that can go into the manufacture of another tube. The unopened bottle of wine in the foreground? One finds more than just birdnests in the muzzles of these guns.
Again, as the name "smooth-bore" implies. The brown paper bag apparently was the wadding for the bottle of wine.
Here's the 12-pound howitzer.
In 20th century warfare, howitzers are guns characterized by their high trajectory, the arc of flight, of the projectile. They almost "lob" shells into the target. During the time of the Civil War "howitzer" had a different meaning that had nothing to do with trajectory.
12-pound Howitzers were the same caliber as their big brothers the 12-poound Napoleon, that is they both fired the 12 pound ball. but the howitzer weighed about 1/3 less than the Napoleon, a savings of metal as well as the horseflesh to tow one of these things around. The difference was made up by the size of the powder charge. As the tube walls of the howitzer were thinner and had less mass the full-size Napoleon, the howitzer simply used a much reduced powder charge, lessening the pressures on the tube but also reducing the effective range of the gun. The trade off was between weight, available resources (bronze and battery horses) and range.
It wasn't a very good bargain. The reduced range of the howitzers meant that the battery had to move much closer to the action, well within range of not just counter-battery fire by enemy artillery, but by enemy infantry as well.
The muzzle ring 0f the 12-pound howitzer is chock full of information regarding its manufacture.
There seems to be an obstruction at the far end of the breech of this bronze gun, a rusty obstruction, a spherical, rusty obstruction! Sometimes its not just bottles of wine you find down these tubes. (click on image and decide for yourself)
The yankees had four batteries of these at Antietam and they served continuously throughout the day. Their extended range, about two and one half miles, meant that they could reach out and "touch" nearly every part of the battlefield all the while remaining safely out of range of Confederate artillery.
both the twist of the rifling as well as the pitting of the iron due to exposure to 150 years of weather.
Here's a reminder of why the Civil War is often referred (erroneously or not) as the "first modern war".
The 12-pounder, breech-loading, Whitworth was manufactured in England and imported by both sides though its most notable service was with the Confederates. Breech loading made for safer operation by the crew, faster loading, and the nature of loading from the rear rather than the muzzle made for a tighter fitting projectile that popped out of the barrel like a champagne cork, rarin' to go. These things were extremely accurate and had a range up to 5.5 miles! This extreme reach served to work against their most effective employment. With limited optics, erratic fuses, and the lack of visibility created by smokeless powder, these guns weren't often used at the extreme ranges they were capable of. What sense would it make to fire farther than the battery commander could actually see (even with binoculars)?
The lands of the Whitworth rifling are quite worn on this example. And a look down the tube reveals the twist as well as...
three swallow eggs! It's not just bottles of wine and cannonballs you find down these things.
This is one of two at the park that features the old fashioned lifting "ears" above the trunnions. These handles fell into disuse as another savings in casting material.
The gaping maw of the massive 24-pounder. Typical of a howitzer, the tube walls are quite thin to sustain the firing of a 24 lb projectile. Here's the trick:
There was another characteristic feature of howitzers that set them apart from other bronze guns. Click on this image to enlarge it and that feature will become evident. At the very base of the breech you can see it reduces to a diameter about half that of the rest of the tube. This smaller cavity accommodates that much-reduced powder charge, which will propel the heavy projectile down range without creating the high pressures that could burst the barrel. The secret of the howitzer revealed.