"Artillery Bounce-through in other rulesets?" Topic

I use Empire III & V

Out of interest do any other rules use artillery bouncethrough and if so how is it calculated. Thanks

I recall Bruce Quarrie's "Napoleon's Campaigns in Miniature" from back in the 70s include this.

The Wargame by Charles Grant uses bounce sticks for round shot.

CLS I and II use bounce sticks.

If I remember correctly ATKM used a diminishing pool of dice. Hits in one rank were set aside, and missed re-rolled for the next rank or unit.

Yes, in NCIM your deemed first graze was in front of the target unit and weapon types had a 'penetration' distance or bounce-through value from that point on. Fire took effect on units in the line of fire up to that distance beyond the target. You just resolved casualties again for each unit thus hit, with the appropriate range modifiers.

You were also supposed to roll for accuracy, i.e. it was possible to miss short, over or to either side of the target. If you missed short you measured penetration from there, if you missed long you did no harm to the intended target but you might hit a unit beyond it, and if you missed to either side you resolved fire against whatever you actually had hit, if anything.

It was a bit of a faff, but it is quite a good template for how to handle rockets – they take effect where they end up, which may not be where you aimed them.

Any unit behind the line of fire of the targeted unit and within 5" (28mm) is subject to bounce through. Roll 2D6s again as per the parameters of the initial roll for the main target and halve the results. General de Brigade.

Newbury Rules calculated losses on the 1st unit, with successive units in the line of fire having the previously calculated losses deducted until the net value was zero or less.

Other rules with bounce through AFAIK: Shako, Carnage & Glory, General de Armee, Valmy to Waterloo, LaSalle II.

" Over the Hills" sets a penetration distance beyond the original target. This varies depending on cannon calibre 12 inches for 4 pounder, 36 inches fir 12pounder, but never exceeding the maximum range for that particular cannon . Casualties are calculated on any unit in the penetration zone, using half the original roll to hit.

Quick basic of Empire III bouncethrough
Ranks of figures after target x %10 for half the distance fired

WRG 1685-1845:
- Page 35
- Danger Zones and Overshoot Targets
- If element doesn't hit anything then test any others in danger zone.

General d' Armee- 1d6, 4+ hits.

I think it's a 6 to hit in Lasalle 2 for bounce through.

Cheers,
John

General de Brigade Deluxe Edition bounce through rules for 15mm figures are basically a unit 8cm or less behind the target unit receives 1/2 the casualties of the target unit.

5 inches or less behind for 25/28mm figures.

Napoleon at War use a bounce through rule called Ricochet.
How it works is it hit the first unit, friend or foe, behind the target provide it is within the artillery firing zone, the unit is not behind a hill or a village and that it is within the specified distance.

"Bounce Through" is NOT a game gimmick looking for a rule set to settle into. It is a real major tactic in napoleonic warfare. Somehow all our smart historian players can not htet their heads around that an explosive shell (which kills just around its burst radius) is entirely different weapon system than an kinetic energy cannon ball, which has a long and narrow kill zone, when used properly. (a.k.a. bouncing along under head height through people above ground). A cannon ball going at an shallow angle thu one or several lines of infantry will (literally) go through many more bodies (5-10X?) than firing directly perpendicular at a line- where you might hit 3 men or none.

Hey Bills Fan,

This thread IS about game mechanics or "gimmicks". If you want a historical academia discussion, you may want another thread.

Agree it happened, so what do your rules do to come to same conclusion.

"Bounce Through" is NOT a game gimmick looking for a rule set to settle into. It is a real major tactic in napoleonic warfare.

That's not entirely true. Gunners aimed to hit the primary target with a grazing shot to knock down as many ranks as possible but, there was no calculation on where the ball would bounce after that because the height and direction of secondary bounces were nowhere near as predictable as the first. This unpredictability was simply down to the ground the ball was bouncing over – it wasn't called ricochet fire for nothing.

Unpredictable bounce is why the British used Spherical Case (shrapnel) so much – concentration on the primary target being a better use of effort than hoping 'bounce through' to units beyond would give a second bite at the cherry, and against French columns of columns when round shot would seem the obvious choice.

Furthermore artillery was nowhere near as accurate as one might think – targets beyond 800 – 900 yards being commonly thought a waste of powder (unless very well supplied with same or multiple targets were concentrated) – at ranges beyond 900 it was hard enough to hit the primary target.

Bounce wouldn't be considered at all for targets inside the second point primitive (about 400 yards). This was generally regarded as point blank range. The second point primitive is the point at which, after leaving a horizontal muzzle (first point primitive), the ball would pass back through the horizontal line on its parabolically curved flight: Apparently all shot naturally goes upward (due to recoil?) on leaving the muzzle – thus giving two points when the ball is at the same height as the horizontal barrel before falling to earth due to gravity.

Also, a final thought on bounce through, second lines were usually a long way back (much farther than one sees on an artificially 'shallow' wargame table): In the SYW 500 to 700 yards was considered a proper distance between the first and second lines – I don't have information on Napoleonic line spacing but as artillery hadn't changed much I imagine similar distances applying.

In consequence of these reasons, although a bounce through seems like a perfectly reasonable thing, its actual battlefield effects were more by luck than magic and I generally don't think it worthwhile exploring.

Just my two penny worth.

Good points olicana. I think though that if the mechanism is simple, its inclusion and occasional use when it does apply is not too onerous. And might encourage greater line separation :^)

Cheers
John

And might encourage greater line separation

It largely depends on the depth of your table and figure scale / ground scale. In a 6mm game on a six foot wide table with a reasonable artillery range it's entirely possible, I suppose, to think about such things.

Depth always seems to be something of an elastic distance in 28mm games due to 'approximate' ground scale. This partly because weapon range and move distance in relation to time scale often make no sense whatsoever. In consequence, although my supporting lines might well be within artillery range of the enemy (so they can effectively support the front line in game terms) it's probably better to think of their relative distance from the front line as artificially shrunk to allow the rules to work. And I'm happy to 'suck it up'.

FYI

Anyone wanting to understand why cannon balls lift above the line of flight? NB It's not because of recoil, but physics. See link

Also, for info on effectiveness see.

Muller, Wilhelm (1811) The Elements of the Science of War vol 2, page 136 onwards
link

Of particular note
- page 143 on the impact and bounce angles (para 3) and
- page 148 (section 737) on bounce and impact on lines/columns.

"why cannon balls lift"

Do rounds fired from smooth bore artillery pieces spin about an axis of rotation with alignment to the line of flight as shown in the linked article ?

Scott,

The problem with this book is it's almost certainly all paper maths, i.e. theory and it all assumes hard level ground, i.e. a perfect bounce surface, because if it didn't the maths would get far too complicated. Like the massive sections on multiple complex drill maneuvers I'd take a lot of this with a large pinch of salt. What is interesting on page 148 is the relationship between firing at a line and enfilading it; a massive difference most rules don't reflect, but that a 'bounce stick' will go some way to representing. It's also interesting to note the theoretic small differences across the weight of guns. If in real life it was that small then why did everyone go for bigger guns as time went on.

Michman,

Yes, the problem for the theoretician being that unlike deliberately spun projectiles or even cricket balls they do it unpredictably because a) they are not perfect spheres but their imperfections are not repeatable b) their exit from the gun barrel is not precise, due to the unevenness of the wadding and minor imperfections in the barrel. This some will spin more than others and each will spin about its own axis, so some vertical others lateral, most some cocked combination of both.

@Mark J Wilson

As I understand it (and please correct me if I get it wrong) …

The rounds are approx. circular in cross-section. The deflagration of the powder is highly irregular compared to modern standards due to poor mixing and rather varying granularity and inconsistent compression from tamping – and – because the powder's ignition is propagating from a toucehole above the charge. This almost always propels the round along the smooth bore at some angle other than parallel to the center of the bore. The round thus bounces one or more times against the bore before exiting the piece.

I should think the result would be no axial rotation (on any axis), but some degree of wobble or erratic flight for non-homogeneous rounds (poorly cast roundshot, any shell, most cannister) where the center of mass of the round is not its physical center. I would guess the sports analogy would be a throwing a knucle ball – but I am not too sure I understand baseball or cricket.

Again, please correct me if I dont understand rightly.

Gunners aimed to hit the primary target with a grazing shot to knock down as many ranks as possible but, there was no calculation on where the ball would bounce after that

Additionally, on most battlefields, the gunners probably couldn't really see what was behind their primary target, anyway. They likely assumed that the enemy was coming at them in at least two supported lines, since that was S.O.P. for most armies.

But the fiddly stuff that all games & gamers do, trying to get the perfect angle to hit the maximum number of targets, spotted from a helicopter a mile over the battlefield… I doubt that bears much resemblance to the sort of calculations an artillery captain made at the time.

So maybe a better reason to count bounce through as what it is, randomly hitting troops behind as is said on 3rd day of Gettysburg the rear area was pummeled as to eventually clear it of any creature

Artillery men such as Tousard wrote of direct fire and random fire. Random fire was to 'interdict' an area rather than targeting a specific target. That random fire was also used over slopes when the other side could not be seen, but it was suspected troops were there, such as the French artillery fire during the afternoon of Waterloo.

In our game, random fire is pass-through fire and it is treated as interdicting the area behind the units taking fire.
Interdicting as creating difficulties in moving or causing disorder rather than serious casualties. Clausewitz wrote about traveling the battlefield as a courier and knowing how close he was to the front lines by the type and volume of artillery fire was coming his way.

Marshall Lannes would have something to say about the "type and volume of artillery fire [that] was coming his way" in the form of "bounce through".

Wargame rules need bouncethrough to punish players from packing to many troops in a tight area. No matter how you look at it, the more troops in an area, the more casualties – this holds true for cannon fire and even howitzer fire and grenades in later periods. Bouncethrough or area fire is an excellent rules mechanism for this.

Have read in a few accounts Blucher was only one maybe who thought lobbing shells over a hill though no idea what was on the other side would be a benefit.

I had a game recently using "March Attack" rules. I scored more hits on a battalion in the second line than in the first while targeting the front line. The chance to hit the second line is half that of the first. 5" danger area behind the first target, that is 300 yards. We might reduce that to 3" just for the look. We use 6mm minis.

Hi Mark

WRT to "… The problem with this book is it's almost certainly all paper maths, …"

Can you explain what is wrong with the maths and physics that underlie this?

Michmann

Acknowledging that in practice a cannonball is unlikely to perform as finely as the maths. Not only because of irregularity in its own composition but also because it starts fixed to a wooden sabot which needs to break off and that seems likely to disturb its flight.

This is the same math and physics used to design golf balls (and flight-enhancing dimples) or the physics of how to impart spin to cricket and baseballs.

The following may help answer the question.
link

I've queried why does this airflow from the powder not impart spin to left or right etc. I've been told by a muzzleloader shooter that it's essentially accidental. Namely due to gravity the ball (in a cannon or musket) drops to the bottom of the barrel due to gravity. In their long-range shooting, they consciously angle the barrel when loading so that the ball is on the "bottom" to try to achieve the long-range shots. They have tables which help predict the flight, given the powder, weight etc. Dimples (like golf balls) are not allowed as it enhances spin and lift.

In effect the larger windage at the "top" of the ball versus the sides and none at the bottom means the expanding gases pass over the ball more than elsewhere. This affects the spin, and to some degree lessens the "bouncing" inside the barrel.

The key is the lift is not a consequence of recoil, which apparently, only becomes significant at the time of departure from the barrel. Just as with modern rifles.

Scott, You asked "Can you explain what is wrong with the maths and physics that underlie this?". There is nothing wrong with the maths and physics if there is no weather, the ground is always level and of a very hard consistency, effectively concrete, etc. The problem with real life ballistics is the number of variables is too large and the accuracy of measurement of those variables is too poor for the theoretical answer to be anything more than a vague approximation.

Michman,

I wouldn't say the round bounces down the barrel as it is held by the wadding [if loaded properly], but otherwise you are correct. Effectively no two rounds will leave the barrel on exactly the same line. If you have a ball that is not perfectly smooth and exactly spherical then the moment it is in the air the imperfections will tend to make it deviate, including inducing variable spin.

You are also correct the degree of ramming of the round effects performance, my wife is an ex muzzle loading cannon rammer, there is just the right degree of oomph, too much is as bad as too little.

Quarrie's rules specified that you added 1 per x ranks deep including when firing down a flank. The limit to what you added was the depth of the formation or the bounce range of the round, whichever was lower.

In theory this did make enfilade firing absolutely devastating because a line that's 3 ranks deep from ahead is 200 ranks deep end-on. In practice though you had to hit the formation end-on to achieve this effect, which is highly unlikely. You were far likelier to miss it altogether, and if the target was moving you wouldn't get to enfilade it for long.

Empirically, diagonal fire was the best compromise except that you were also expected to fire at the nearest target.