Gentlemen,
This is certainly not my area of expertise (not that I even have one of those) but Cuz' Barts' question begs a mathematical moment.
The 7" DB Brooke Rifle had a range of approximately 4.5 miles. 1 mile = 5,280 feet. 4.5 x 5,280 = 23,760 feet. Allowing a very high muzzle velocity of 1,500 Feet Per Second a projectile would be aloft for 15.84 seconds if fired to this maximum range - well outside of the burn time of a 10 second fuze (if posible to fire at 0 degrees elevation - obviously impossible) . If the projectile is fired with the intent of exploding directly on or in a target then the math, worked backwards, dictates a range of exactly 2.8409..... miles.
Seems to me that the art of "gunnery" was, of necessity, complimented heavily by the art of "fuze cutting". Enter the matters of Mortars, howitzers and indirect/high angle fire and the variables could drive even a great gun captain to drink.
Afterthoughts include the fact that there are two naval engagements that might offer something to ponder insofar as ranges for such.
March 8, 1862 at Hampton Roads CSS Virginia opened fire on the USS Cumberland (a large stationary target) at a range of 1,500 yards. This shot was fired by an outstanding naval gunnery officer (Charles Carroll Simms) in the immediate presence of two more outstanding naval officers - Franklin Buchanan (in the US Navy since 1815) and Catesby ap R. Jones (among the best ordnance officers in either navy with 30 years in the US Navy). The first two rounds caused heavy damage. The Cumberland received the fatal blow from the 1,500 pound iron ram at the Virginia's bow. The maximum time elapsed from firing the first round at 1,500 yards (assuming Virginia had an 8 knot maximum speed) and reloading to fire the second shot was no more than 11 (10.8 actually) minutes - extremely fine work requiring a superb performance in a crowded casemate crewing a large caliber gun. Remember, the subject of this paragraph was range at initial engagement.
The second example would be that engagement between the CSS Alabama and the USS Kearsarge off Cherbourg Harbor on 19 June 1864. Again, the primary CSN weapon was a 7" rifle (Blakely). The range was approximately 1,000 yards and the battle continued at that range more or less until the ships had circled 7 times.
Given the stated engagement ranges of 1,000 to 1,500 yards for hard hitting rifles the time of flight for projectiles would not exceed 3-4 seconds.
I would think that the greater ranges where the higher fuze burn times would apply were between land batteries or land batteries and vessels. IMHO.
Merry Christmas everyone.
