Thoughts on 18th Century Musket Accuracy

[cannonman61]

I have been working on this for some time. I thought you might find it enlightening or at least interesting.
I am sure SoM will find some of what we've discussed in here.
Also added in downloadable form MSWorks.

CM   


Thoughts on 18th Century Musket Accuracy

   When one thinks about the battles fought in the 18th century and the tactics in vogue at the time one naturally thinks of them, the tactics, as utterly insane. The linear infantry tactics we so deride today; large numbers of men in tightly packed formations all adorned with brightly colored uniforms essentially lined up and firing at each other at close range, were in fact dictated by the real and practical matter of the accuracy of the standard military weapons of that day. In fact as a matter of course when thinking about these tactics, one would expect that the casualty rate would be akin to wholesale slaughter, when in fact the ratio of actual battle casualties in 18th century warfare were, in reality, quite low. ( See chart included below)
   As noted in the chart of major battles of the Revolution seen below, the average battle casualty ratio is only about 13% in both killed and wounded. That is to include the reality that for every man killed on the field there would be approximately 5 men wounded to some degree who may well die of their wounds later, to men who will recuperate well enough to eventually rejoin their unit as effectives.
   With battles fought with tactics such as these and at such close ranges as observed by contemporary writers of the period, why were the casualty ratios so low? A look at the capabilities of the military muskets of the period, in particular their accuracy, may help to explain this interesting and vexing question.
   The primary infantry weapon of the 18th century was a large caliber smoothbore flintlock musket. This weapon, whether it be a British Brown Bess, French Charleville, or American Committee of Safety musket, all had the following general characteristic; these weapons were not so much built for accuracy as for the rapidity of reloading.  Given the manufacturing and metallurgy technology in use at the time this becomes perfectly understandable. Let's take a look at those considerations.
   All of the standard infantry weapons used on the battlefield in the 18th were very much the same in form and function and had nearly identical performance especially as far as the speed of loading and accuracy was concerned. As they were used in this period a soldier was expected to load and fire on command, four times a minute, while the effective accuracy was only about 50 yards, perhaps 80 if a man was blessed with a particularly well bored specimen. This inherent level of short range expectations of accuracy led to the " Whites of their eyes" distance immortalized at  the Battle of Breed's Hill. ( Bunker Hill to the laymen)
   Smoothbore musket barrels of the period were not a solid billet or bar that was bored into a tube, rather they were constructed of 3 or 3 rectangular metal bands forge welded and coiled or bent around a solid iron mandrel or the correct dimension. The metal was heated white hot , wrapped around the mandrel and hammered or forge-welded into a more or less seamless tube. Here, the problems with accuracy begin with this manufacturing process which varies by a great deal with the imperfections in the welds, imperfections in the steel, and skill of the individual iron worker that varies between one manufacturer and another. Even if the bore were perfectly straight and true the front sight/bayonet lug might not be perfectly sized or even place correctly on the surface of the barrel. In fact, one British officer complained: " The barrels of different firelocks (muskets) vary in thickness, and the Sights placed upon them at the muzzle by which the bayonets fix, vary no less in size or position" Clearly, there was no ISO2010 for quality control in the 18th century. To pass muster into service of the Crown, all that had to be done for a musket was for the barrel to hold "proof". That is it must be fired with a double load of both powder and a double ball and suffer no VISABLE signs of damage. Sometimes the hidden stress fractures still claimed a soldier as a musket may hold proof once and then fail in service when used over time.
   Adding to the list of potential accuracy thieves is the fact that the lead balls used in these weapons were purposefully cast several thousandths of an inch smaller than the bore in order to speed reloading to the maximum degree. For example, the British Brown Bess was nominally .75 caliber while the ball issued for this weapon was .69 caliber. The French and Americans using the Charleville which was .69 caliber, issued a .62 caliber ball for use. In both case the ball is .06 or .07 of an inch smaller than the bore of the weapon firing it. This leads to a great deal of wiggle room in the barrel as the ball accelerates down the bore at firing and the ball can take an angle poorly conducive of accuracy as it leaves the barrel.

   Next in the cast of characters robbing these weapons of their accuracy potential is basic physics.  No matter how fast an object moves horizontally to the ground, it is acted upon by gravity at the rate of fall towards earth of 32 feet per second. This being so, a ball fired from a 18th century military musket has a velocity of only about 1200-1400 feet per second and  since the projectile is a sphere with more than half of its surface area subject to wind resistance and friction as it flies thru the air, so that muzzle velocity drops off rapidly once the ball leaves the barrel. In light of all this, at a distance of just 50 yards a ball with a muzzle velocity of 1400 FPS will have dropped by as much as 6 inches by the time it reaches the target. And modern shooters complain about having to deal with modern trajectory curves!
   Lastly let's look at outside or environmental issues effecting accuracy. Wind. Today we dope the wind at long ranges and are used to doing so only when we shoot at ranges in excess of 200-300 yards and there is more than a minor cross wind. For the 18th century soldier it was more problematic. Even a slight breeze on a spherical projectile moving at the low forward momentum a musket ball had would be highly susceptible to wind drift or lateral inaccuracy causing a round to go right or left with the prevailing wind. Intuitively one would think, "So what, with the enemy packed shoulder to shoulder it almost certain to hit one of them.". True to a point. However, after the British experienced the massive casualties at Breed's Hill they quickly changed their formations to "open order" - about an arms length between men- so the chances of randomly striking a man , rather than the now created space between them, were effectively cut in half.
   Also falling under environmental conditions not conducive to accuracy it must be stated that the black powder of the day while not only of varying quality and power, also produced an almost impenetrable veil of thick, pungent, white smoke. It has been calculated that each musket produces a cubic foot of this smoke with each firing. Multiply that by the hundreds of muskets firing on both sides repeatedly along with massive clouds produced by the artillery and you some idea of the true origin of the term "fog of war". You can now imagine how difficult it becomes to see a man standing very near you, let alone try to sight on a man more than 50 yards distant.
   Lastly, as if the former weren't enough problems relating to practical accuracy in the field, we have the command structure of the 18th century army. A soldier NEVER fired without being ordered to do so. While it is true he was expected to be able to load and fire 4 rounds a minute, the actual command to fire was nearly always by volley. All soldiers discharging their weapons all at one moment for maximum effect(physical and psychological) on the enemy. Under the conditions stated above it is a very real challenge for an experienced marksman to hit a specific target at a specific moment which is what was asked for in the firing commands of this time. It is one thing to at your own pace, pick out and carefully aim at a target and then carefully squeeze off a shot and quiet another to be expected to " make ready....take sight.....FIRE!" by command with any degree of expected accuracy.
   Given all of the above parameters and  variables; ill bored muskets, poor metallurgy, undersize ball, poor or degraded powder in the cartridges, and all the smoke noise and confusion of the battlefield, it's a wonder there were any casualties at all!

Battle Casualty Chart

Battle                  Continentals        Killed        Percentage        Crown          Killed        Percentage      Victor                    
                             Engaged         Wounded                               Forces       Wounded        

1. Lex/Concord        3763              90                   2.5                1800              247                 13       American
2.Breed's Hill           2000             411                  20                 2400             1054                44         British?
3. Long Island         3500             1400                40                 1700               377                20         British
4. Kip's Bay              900                 60                  7                  4000                  12                .25       British
5. Harlem Heights     2000               130                  6.5               5000               171                 3.5       British
6. White Plains        1600               154                  9.5               4000               313                 7.5       British
7. Ft. Washington    2900               149                  5                  8000               452                  5.5      British
8. Trenton              2400                  4                    .2                1400               114                 8       American
9. Princeton            4000               105                  2.5               1200               210                18      American
10 Oriskany              860                200                23                  1000               150                15         British
11 Bennington         2300                 80                   3.5                1442              207                15     American
12 Brandywine       11000               950                 8.75             12500              570                4.5       British
13 Paoli                  1500               150               10                     900                  9                 1          British
14 Germantown      11000              673                  6                    9000              520                6          British
15 Bemis Heights     9200              200                  2.5                 2200              426               19       American
16 Saratoga           3000              283                  9                    3000              600                20      American
17 Monmouth       11000              479                  4.5                  9500             1215              13        Draw
18 Savannah Siege  850                83               10                      3500                13                .5         British
19 Paulus Hook       300                  5                  2                        250                50               20      American
20 Camden          3052              1050             34                    2239              313              14              British
21 Cowpens        1025                  72               7                    1100              329              30            American
22 Guilford Ct      4400                 261              6                    1900              532              28              British?
23 Hobkirk Hill      1551                 134              9                      900              208              22             British
24 Eutaw Spring   2200                 514            23                    2000              436              22              Draw
25 Yorktown        9500                   88             .75                  8885              526               6            American
   
         

[Cowdog]

Interesting thoughts. I have a suspicion that seems to be comfirmed by at least some research that colonial civilians were more careful loading (Tight Patch to make up for undersized Ball).

[Son of Martha]

This book:

http://www.amazon.com/Firepower-Weapons-Effectiveness-Battlefield-1630/dp/1885119399

Has the best attempt at analyzing accuracy of smoothbores in combat conditions that I have seen.

AIRC, his conclusions were that in most battles hit percentages were below 1%.  He does mention a couple instances of either unusual battles or parts of larger battles where the tactical situation led to (apparently) greater effectiveness (up to around 5% hit rate or so).  He also explains HOW he came to the estimates, with the historical data and the assumptions used.

BTW, he also covers cannon... .  The conclusion there was that across the whole period (1630-1750) roughly one casualty was produced for each round of artillery fired in anger.

Good read.

Note that our hit percentages in combat today are not so very different, either...  

SoM

[Fred]

Note that our hit percentages in combat today are not so very different, either...  

SoM

    Actually, the last stat I saw was for Vietnam, and it was 200,000 rounds to produce one enemy casualty.

    A bit under 1%...

    Maybe we should re-evaluate smoothbore muskets.

    Naw. Let's teach 'em to shoot!

[Greg in MO]

I would guess it is difficult to calculate accurate data from those numbers (excellent compilation by the way), as I would think a large number of casualties were caused by the bayonet, on individuals who may or may not have been wounded in during the volleys.

Even during the Civil War, General Jackson still considered the bayonet the primary weapon of the infantry.

Greg