This nice example of a 10-pounder Parrott rifle is in terrific shape: its limber, carriage, barrels and all other things weaponry are in terrific condition. These rifles are more rare than the 3-inch ordnance rifles and the Napoleons which seems to be everywhere. The Parrot is very similar to the 3-inch ordnance save for the band around the breech which makes it distinguish itself from the 3-inch ordnance. Also, some Parrott have a flare at the end of the muzzle (eliminated in 1863) and the 3-inch does not. Another similarity the two rifles share is the deep incised stamp that runs along the outer muzzle which make identification very easy and accurate. I sometimes notice writing on both of the cannon's trunnions. On the right trunnion (viewer's left), the trunnion reads R.P.P. R.P.P. are the initials of Captain Robert Parker Parrott, the inventor of this waymark, the parrott Rifle. On the left trunnion (viewer's right) the trunnion is stamped 10 PDR which of course refers to the weight of the projectile ordnance. I have also found stamped at the top of the breech information about the bore which simply reads: 3. IN. BORE.. The bore was not enlarged to a 3-inch size until 1863 so that bit of information at least acts as an identifier. Curiously however, this Parrott rifle does not have any identifying marks on it. As a result, this guns is anonymous as I could not recover the registry or foundry numbers.
The manufacturing of the gun carriages is an interesting story. After the war, Calvin Gilbert conducted a foundry @ Gettysburg and manufactured metal gun carriages to replce the rotted wooden ones. He also cast the battery tablet at this site as well as the other ones about the battlefield. Gilbert joined the 87th Pennsylvania Volunteers when the "Rebellion" broke out. Since he was musically inclined, he was made a member of the regimental band. In early 1863, he was promoted to the rank of Captain and sent to Washington D.C. for commissary duty. He served in that capacity until the war ended in 1865, and at war’s end earned the brevet rank of Major. 
After returning home to Gettysburg, Major Gilbert moved his family to the town of Chambersburg, where he served as the Superintendent of Schools. He also opened an iron foundry there in 1868. When Calvin learned, nearly thirty years later, in 1894, that the Gettysburg Foundry was available, he purchased it with a business partner & moved his family back to Gettysburg. For the next twenty years, the Calvin Gilbert Foundry created ironworks that are still seen today on many historic forts and national battlefields (this tablet), from upstate New York to Florida to Lookout Mountain. Gilbert lived to be 100 years old and attended the Last Reunion of the Blue and Gray for the 75th anniversary of the Battle of Gettysburg when he was 99. He was a most remarkable man who lived an amazing life.
There is an excellent excerpt in the American Guide Series about Gilbert attending the 75th reunion anniversary.
The rifle and the tablet are located @ the intersection of Benner's Hill Loop and Hanover Road (Pennsylvania Highway 116), on the right or west side of the road when traveling south on Benner's Hill Loop. This monument is the second monument on this road, past the 
Graham's Rockbridge Artillery Tablet, which is also on the same side of the road. To the right of the tablet is this 10-pounder Parrott which represents the Chesapeake Battery. Parking is available all up and down the narrow road. Take care to not park on anything remotely green looking as Park Police will happily ticket you. I visited this site on Monday, July 1, 2013 on the 150th anniversary of the Battle of Gettysburg @ 1:02 PM, EDT. As always, I used my trusty and oft abused Canon PowerShot 14.1 Megapixel, SX210 IS digital camera for the photos.
About the Foundry
As far as I know, these rifles were made exclusively @ the West Point Foundry in 1863. The West Point Foundry was an early ironworks in Cold Spring, New York that operated from 1817 to 1911. Set up to remedy deficiencies in national armaments production after the War of 1812, it became most famous for its production of Parrott rifles and other munitions during the Civil War, although it also manufactured a variety of iron products for civilian use. The rise of steel making and declining demand for cast iron after the Civil War caused it to gradually sink into bankruptcy and cease operations in the early 20th Century.
In 1835, Captain Robert Parker Parrott, a West Point graduate, was appointed inspector of ordnance from the foundry. The next year, he resigned his commission and on October 31, 1836 was appointed superintendent of the foundry. It prospered under his tenure, and was the site of numerous experiments with artillery and projectiles, culminating in his invention of the Parrott rifle in 1860. During Parott's tenure, in 1843, the foundry also manufactured USS Spencer, a revenue cutter which was the first iron ship built in the U.S. The foundry's operations peaked during the Civil War due to military orders: it had a workforce of 1,400 people and produced 2,000 cannon and three million shells. Parrott also invented an incendiary shell which was used in an 8-inch Parrott rifle (the "Swamp Angel") to bombard Charleston. The importance of the foundry to the war effort can be measured by the fact that President Abraham Lincoln visited and inspected it in June 1862.
SOURCE
About the Gun
The most common rifled field artillery piece in Civil War service was the 10-pdr. Parrott . The gun was invented by Robert Parker Parrott, a West Point graduate. He resigned from the service in 1836 and became the superintendent of the West Point Foundry in Cold Spring, New York. He created the first Parrott Rifle (and corresponding projectile) in 1860 and patented it in 1861. SOURCE This Parrott design went through several improvements during the war. The U.S. M1863 10-pounder Parrott was slightly modified from the M1861 pattern; the bore was increased to 3.0 inches in 1863 with a matching Parrott shell, to make its ammunition consistent with that of the new 3-inch ordnance rifle, and the muzzle swell was eliminated. By 1864 the 3-inch Parrott was standardized and most of these 2.9-inch guns were withdrawn from service. Parrotts were manufactured with a combination of cast iron and wrought iron. The cast iron made for an accurate gun, but was brittle enough to suffer fractures. On the Parrott, a large wrought iron reinforcing band was overlaid on the breach. Although accurate, the Parrott had a poor reputation for safety and they were shunned by many artillerists.
I also remembered the Antietam Battlefield people placed a small identification marker sticking out of the ground next to one of their Parrotts which read:
10-POUNDER PARROT RIFLE
The cast iron rifle with its band of wrought iron reinforcing
the breech was a modern weapon of the day. It was effective at
moderately long range. The 20-pounder, similar except for size,
was the heaviest rifled cannon used at Antietam.
Confederate versions of the Parrott Rifles were built by the Noble Brothers Foundry, the Macon Arsenal in Georgia and Tredegar Iron Works, Richmond, VA. Confederate cast Parrott rifles used seven hook-slant or "Brooke" type rifle grooves, and can be identified by the taper on the trunnion side of the reinforcing band.
One of the pages of the Historical Marker Database also provided some interesting and corroborating facts about this weapon and history about the rifle: This 3-inch Parrott Rifle was produced at West Point Foundry in 1864, well after the battle. At the battle, the Parrott Rifles on the field were actually 2.9-inch bore models, commonly called 10-pounder Parrotts. Problems arose with logistical support, since similar shells were made for the 3-inch Ordnance Rifles. The Army opted to replace all 2.9-inch weapons with the slightly larger bore, and West Point began producing "new" Parrott rifles with 3-inch bores.
About the Battery
The Chesapeake Artillery served as a member of Latimer’s Battalion with in Ewell's Second Corps and Johnson's Division. The battery was commanded at the Battle of Gettysberg by Captain William D. Brown, who was mortally wounded on July 2nd. 
At the Battle of Gettysburg, during the artillery duel with the Union batteries on Cemetery Hill, As Brown spoke to his men in position on Benner's Hill, a solid shot smashed into his right leg, passed through his horse, and then broke the bones in the left leg. As the horse fell to the ground, three of Brown's ribs were broken. He was one of the first to fall, having both legs shattered, but somehow managed to survive his dreadful injuries for several days before dying. Captain Brown was taken to the Christian Benner Farm and treated here for his wounds. Upon his death, he was buried there under a large walnut tree east of Rock Creek. Brown's body was removed from its temporary grave on July 31, 1863, and buried in Green Mount Cemetery, in Baltimore, Maryland.
The tablet marks the position and actions of Brown’s Chesapeake Artillery on July 2, 1863 reads as follows:
Army of Northern Virginia
Ewell's Corps - Johnson's Division
Latimer's Battalion - Brown's Battery
The Chesapeake MD. Artillery
Four 10 Pounder Parrotts
July 2 Took position here about 4 p.m. and was engaged for over two hours in a severe conflict with the Union Batteries on East Cemetery Hill and Stevens Knoll. Capt. Brown being severely wounded one of his guns disabled and his ammunition almost exhausted the Battery was withdrawn by order of Gen. Johnson.
July 3 Remained in reserve and not engaged.
July 4 Withdrew from the field with the Battalion.
Losses - Killed 4 - Wounded 12 - Horses killed 9
The rifles (incorrectly called cannons) are also identified in the NRHP nomination and narrative form.
From the Nomination Form:
Civil War Tablet that marks position of Brown's Chesapeake, Maryland. CS Battery July 2-4, 1863. Narrates events associated with the Battery during the Battle.
Short Physical Description:
Tablet w/ 1 cannon. Cast iron tablet, 3'8" x 3'4", with raised inscription painted in a contrasting color and mounted on fluted cast iron post. All 4'4" H. Cannon at right of tablet. Tablet cast by Calvin Gilbert, founder.
Long Physical Description:
Located at Benner's Hill, south side of PA 116.
My Sources
1.
NRHP Nomination Form
2.
Stone Sentinels
3.
Virtual Gettysburg
4.
Draw the Sword
5.
Find a Grave