I'm not sure I follow this. Do you mean artillery practice as in "the way artillery was used in the Civil War", or as in "the fundamental limits of gunpowder artillery"?I have limited knowledge of the battlefield circumstances of the F-P War but am confident stating that artillery practice as of the Civil War would have significantly diminished a range advantage such as you point to.
Because it seems pretty clear that the Franco-Prussian War examples (of firing being given at ranges of multiple miles with effect) would seem to demonstrate that it's not a matter of the fundamental limits of gunpowder artillery, and it seems fairly evident that the Union didn't really care to establish the range at which their field guns could deliver accurate fire at deliberate rates - after all, there's no test data existing, and it wasn't in the acceptance trials for the Parrott or Ordnance as far as I can tell.
Conversely, the British considered the range performance of the Armstrong of critical import in both testing it and considering what to replace it with (where firing took place out to approx. 1.5 miles during the trials).
I'm not really sure I understand the battlefield scenario you're envisaging here, or rather, whether the Civil War image correctly reflects the reality that would be created here.The point about smoke and rapid firing covers a battery creating its own problem but it doesn't address the smoke generated by other batteries on the same side or - just as important - obscuring smoke generated by opposing batteries. It also doesn't address the considerable smoke generated by thousands of small arms on both sides. There were several reasons why much of the actual fighting took place below the test-firing "accurate" ranges.
The situation in which I would expect counter-battery fire to take place is one where the batteries of both sides are around a mile apart, or a bit more (up to two miles if the British artillery has a hill to work with which has good visibility) and probably not during a period when both sides are conducting a maximum rate barrage of either artillery or infantry fire. This is because such periods don't make up the whole of the battle along the whole of the line, or ammunition exhaustion would quickly set in.
For the friendly infantry smoke, British tactics for skirmishing envisaged skirmish elements firing around 1-2 rounds per minute at wide dispersal (a brigade frontage on the order of a mile wide appeared in exercises, though that was shaken out into skirmish order); for the enemy infantry smoke, obviously if there is a battlefield crisis going on then that is where the artillery would be contributing. But during the periods between the battlefield crises, then counter-battery fire is both a good idea and potentially effectual.
Similarly, enemy artillery can't be firing at a rate sufficient to cloak themselves in smoke for the whole of the period of a battle. That is rapid fire and it cannot be sustained; indeed even deliberate firing can't be sustained for a whole day long battle, it involves 1 round per 2 minutes per gun and that is 300 rounds over the course of a ten hour day.
In the Franco-Prussian War, what we have is large Prussian batteries of breech-loading Krupp artillery firing effectively on enemy trenches manned by French troops possessing Chassepot rifles able to fire at 10 rounds a minute, with the guns firing in support of Prussian infantry armed with the Dreyse (which is a breech loading rifle itself, though not as fast firing). They are nevertheless able to effectively use their breech-loading artillery's long range and accuracy to entirely redress and reverse the tactical disadvantage caused by attacking a heavily entrenched enemy with longer ranged, more accurately firing infantry weapons.
If that is the kind of thing that long range accurate rifled artillery can do in an environment where everyone has a black powder breechloader, I do not think that powder smoke is going to be an impediment to effective firing in an environment where everyone has a black powder muzzle loader with about 1/3 to 1/5 the firing rate.
But test firing data establishes a relative comparison. What we have at the moment is the following data:I think you're operating with a misleading assumption that test-firing data establishes equivalent range/accuracy superiority in actual battle conditions. Again, in an era of direct fire and distance siting limitations, the test-firing data becomes to some extent useless. The Whitworths possessed by the ANV at Gettysburg had terrific range (and, of course, complicating breech issues) but they were unlikely to play any meaningful role because of the practical limits. The consensus regarding the two Whitworths at Gettysburg is that they had some psychological effect, due in good part to the bizarre shriek the projectiles made, but no actual damage/physical effect. I'm unaware of any role Whitworths had at Malvern Hill. The Army of the P had a few on the Peninsula but they weren't really used for the reasons stated. The consensus is that they just weren't all that practical.
- the Armstrong was very accurate in test firing out to 2 miles.
- no significant counter-battery fire (or other accurate field gun bombardment) took place in North America at ranges of a mile or more.
We do NOT have the following data:
- the accuracy statistics of the Parrott or Ordnance in test firing.
There may be data in Peterson's Notes on Ordnance, and a footnote referencing this book stated that the mean deviation of the 3" rifles averaged 12 feet at 1,200 yards, but it is not clear if the figure is actually from the book.
There are thus two possibilities:
- the Parrott and Ordnance rifles were comparable to the Armstrong in being accurate at a range of 1-2 miles, and the reason why no counterbattery fire took place is that there is a fundamental inability (relating to troop training or conditions) to do that.
- the reason why no counterbattery fire took place in North America is that it is due to the inability of the guns to perform well enough (i.e. Peterson's Notes actually does contain the 12 feet at 1,200 yards figure and this figure is substantially correct.)
The missing data would determine which of these it was, because if the guns were incapable of it then obviously that is the problem.
Now, we happen to have other suggestive data, about the large Parrott and Ordnance rifles when used as siege guns (where they were at least somewhat effective out to several miles) and deviation data of the large Parrott and Armstrong rifles (inferior to the Armstrong field guns).*
In addition, we have what could be called "negative data", which is the lack of the accuracy statistics for the Parrott and Ordnance field guns.
That negative data is important because it suggests an alternative explanation for the lack of counter-battery fire - which is that long range accuracy was not considered a sufficiently important trait to actually test in the field guns the Union was accepting. This would then mean that they did not consider long range accuracy important.
However, if the "fundamental inability" explanation noted above was correct, then we would expect not to see effective counter-battery fire or long range firing in the Franco-Prussian war. And we do.
This forms another piece of circumstantial evidence around the idea that the limits on long range firing in North America are related to either the gun, or the biases and training/doctrinal deficiencies of the Union and Confederate artillery arm (if the gun is capable of it), rather than a fundamental limitation on the ability of a long ranged rifle to deliver effective fire.
It is for this combination of reasons that I think that the hypothesis "a sufficiently precise field gun in a black powder environment can deliver effective fire at 1-2 miles when used by a trained artilleryman" is more correct than the hypothesis "the Parrott/Ordnance guns were comparably precise to the Parrott/Armstrong gun but it is fundamentally not possible to deliver effective fire at 1-2 miles in a black powder environment".
* those numbers are:
30pdr Parrott at 1030 yards: mean impact from centre of target 16 feet.
12pdr Armstrong at 1130 yards: mean deviation 3.12 feet
4.5in Ordnance rifle at 1820 yards: mean impact from centre of target 19 feet
12pdr Armstrong at 2146 yards: mean deviation 4.44 feet
4.5in Ordnance rifle at 2220 yards: mean impact from centre of target 25 feet
If the 10pdr Parrott is comparable to the Armstrong, and thus around five times more accurate than the 30pdr, it seems like that would be something someone would notice.