I posed your question to Norm Gibson, who shoots artillery in North South Skirmish association matches and is a regular compititor at the Long range artillery matches held at Grayling MI. each summer. There CW cannon (original & reproduction) fire service loads of solid shot at a 4'X 6' target @ 1000yds.
Norm has been featured on several History channel programs,The American Shooter show detailing CW artillery, and provided some of the cannon used to record the sound effects of barshot, chainshot, grape and cannister that was dubbed into the recent movie "Master and Commander".
In 1987, there was a demonstration held where Percussion shell was fired at a target (APC) located over one mile distant by 2 Parrott guns and 2 Ordnance Rifles.
Using elevation and range tables developed during the CW, those guns were able to impact shell within 30 Yd of the target and dust from the bursting shells covered the target.
Norm's responce follows.
Ordnance and Gunnery by Capt. J.G. Benton, published in 1862, has a range table for 10 pdr. and 3 inch guns that goes out to 6200 yards using a standard load and 35 degrees of elevation. Other references have the same or similar tables. So reaching a target the size of a fortification at 1900 yards should not be a problem. Hitting an embrasure at that range would be hard to do. Practical experience at Grayling for the Sesquicentennial shows that Parrotts were reasonable accurate at 2200 to 2400 yards shooting at a target that was at a higher elevation. Hope this helps.
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