Brixia Mortars - Realistically Portrayed In Game?

[Battlefront.com]

Yes, a mortar really has to be one or the other. Either it caters to putting a round smack onto a specific target or it is designed to suppress within a useful radius. Perhaps in WW1 trench warfare precision was more important and that's perhaps where the design of the German and Italian mortars came from. But it seems when the enemy is fairly mobile it is a less useful approach than one focused on suppression.

The Germans dropped their 5cm mortar fairly quickly for a reason.

Steve

[MikeyD]

It's (unfortunately) been awhile since I've played Brits, does anyone complain about the hand-held 2 inch mortar being over-accurate in CMBN? I recall in modern war CMSF the Brit on-map mortar was lucky to hit the broad side of a barn.

[womble]

Yes, a mortar really has to be one or the other. Either it caters to putting a round smack onto a specific target or it is designed to suppress within a useful radius.

Surely an accurate mortar can be made to spread the delivery of its little presents around by the operator introducing variability in the aim point between bombs, if area suppression is required? The converse isn't, of course, the case (a mortar with a designed "random" scatter can't be operated to be precise).

[JonS]

In principle; yes, that could be done.

In practice; I don't think so. I haven't seen or heard of a fire control order that encapsulates such a concept for mortars.

On the other hand, mortars generally fire in at least pairs (more often in fours or more) and on lines-of-fire-parallel, which intrinsically means that the effects of the fire will be spread around. Furthermore, there are limits to the accuracy and repeatability of the sighting system, which will introduce minor variations from round to round, and then there are the really significant sources of round-to-round variation such as manufacturing tolerances (of the round and its propellant), heating of the barrel, the weather, and stability of the mortar baseplate.

All of that tends to distribute rounds around the point of aim, whether that's what the observer wanted or intended, or not.

It is also quite possible for the observer to call minor corrections during FFE to deliberately spread the fire around. 'Add 50', 'left 50', etc, to move the big stomping footprint around in response to the developing tactical situation (maybe friendly troops are getting too close), new intel (the observer spotted some additional foxholes over there), or just a hunch (the observer can see two section posts, and assumes the third section is "over there" on the basis of how a platoon is typically laid out).

Edit: there was also, apparently, a 'searching' and 'sweeping' (or sumfink like that) fire control order that the British used in WWII for their artillery. AIUI, 'searching' caused the beaten zone to be moved in definite steps after each quantity of rounds, adding a bit of range each time, sort-of like an impromptu rolling barrage. 'Sweeping' (again, AIUI) was the same but moved the MPI left-to-right or right-to-left across the front. (Link. Scroll down to 'Fire for Effect') But that was for artillery, which had vastly better comms, computing, and survey capabilities than a mortar platoon. I guess that, in principle, a drill could have been developed to do the equivalent for mortars though.

[womble]

In principle; yes, that could be done.

In practice; I don't think so. I haven't seen or heard of a fire control order that encapsulates such a concept for mortars.

On the other hand, mortars generally fire in at least pairs (more often in fours or more) and on lines-of-fire-parallel, which intrinsically means that the effects of the fire will be spread around. Further more, there are limits to the accuracy and repeatability of the sighting system, which will introduce minor variations from round to rund, and then there are the really significant sources of round-to-round variation such as manufacturing tolerances (of the round and its propellant), heating of the barrel, the weather, and stability of the mortar baseplate.

All that tends to distribute rounds around the point of aim, whether that's what the observer wanted or intended, or not.

It is also quite possible for the observer to call minor corrections during FFEE to deliberately spread the fire around. 'Add 50', 'left 50', etc, to move the big stomping footprint around in response to the developing tactical situation (maybe friendly troops are getting too close), new intel (the observer spotted some additional foxholes over there), or just a hunch (the observer can see two of three section posts, and assumes the third section is "over there" on the basis of how a platoon is typically laid out).

Edit: there was also, apparently, a 'searching' and 'sweeping' (or sumfink like that) fire control order that the British used in WWII for their artillery. AIUI, 'searching' caused the beaten zone to be moved in definite steps after each quantity of rounds, adding a bit of range each time, sort-of like an impormptu rolling barrage. 'Sweeping' (again, AIUI) was the same but moved the MPI left-to-right or right-to-left across the front. (Link. Scroll down to 'Fire for Effect') But that was for artillery, which had vastly better comms, computing, and survey capabilities than a mortar platoon. I guess that, in principle, a drill could have been developed to do the equivalent for mortars though.

Whizzo stuff there JonS

I had in mind (should have been clearer) more the direct lay scenario, though.

[JonS]

Oh, right. Sorry

I think, though, that much of that would still apply. The round-to-round variability would all still be in effect, although because the ranges are less the effects would be less noticeable. But the sights on mortars are designed to aim at something - you lay the crosshairs on that thing, and drop the round. Observe where the round lands, apply a correction (however that's derived), re-lay the cross hairs on the thing, then repeat until the rounds are landing on or near the point of aim, then go for broke.

With something as deliberately basic as the British 2-in mortar it'd be fairly easy to do (actually, it'd be hard not to ), but with a weapon that has optical sights I think it'd be harder. Or less intuitive, at least. I suppose you could still develop a drill to wind on and wind off a bit with each round, but the results would be pretty rough.

Don't forget that light mortars tend to carry very few rounds. The British 2-in (to take that as an example) has ... what is it? 15 rounds in total? Maybe 20? And most of those are smoke. The US 60mm has 30? or 50? Whatever, it's not a lot. If you start throwing those around the place speculatively, you'll quickly find yourself out of rounds, without having solved the immediate tactical problem.

Steve, above, mentioned that light mortars were used issued so that small units could quickly solve minor tactical problems, without having to call on higher level assets. That's true, but they're also there to cover the time delay that is inevitable when calling for a higher level asset. A 25-pr mission from a regiment is going to give you a better effect than the few HE rounds carried by the platoon 2-in mortar. But, on the other hand, you're going to have to wait 10 or 15 minutes for those 25-pr rounds to arrive. Instead of just hoping for the best for the next quarter hour, you can use the limited effectiveness of a light mortar - along with other platoon level weapons, as well as company and battalion level systems - to provide some degree of effect, right now, until the Royal Regiment arrives to once again save the day.

Ubique.

[DavidFields]

Battlefront: "On the offensive the light mortars are designed to suppress (kill is a bonus) enemy strong points while infantry moves. Machineguns have a similar purpose, but of course the two have complimentary pros and cons. On the defensive the light mortars are used to break up enemy concentrations (staging areas, crossing dead ground), suppress the enemy's attempts to take out key defensive points, etc. Again, machineguns are used much the same way."

Thank you, I thought I was going nuts. I agree 100%--which you do not really need because you are more the expert.

Now, do we agree on this: CM2 currently does not quite (to be mild) reflect the quoted paragraph? If the answer is "yes, and we are working on it", I'll just take my fingers off the keyboard and refrain from commenting on the (weekly) mortar topics--hey, I see another one now to look in on.

JonS "Don't forget that light mortars tend to carry very few rounds. The British 2-in (to take that as an example) has ... what is it? 15 rounds in total? Maybe 20? And most of those are smoke. The US 60mm has 30? or 50? Whatever, it's not a lot. If you start throwing those around the place speculatively, you'll quickly find yourself out of rounds, without having solved the immediate tactical problem."

I like this quote a lot, also. And I would expand it to include the situation where one is targeting small quantities of infantry, unless they were extremely important. Since the small number of soldiers would likely just move if targeted, the main reason would be to deny them a specific valuable location.

[womble]

Now, do we agree on this: CM2 currently does not quite (to be mild) reflect the quoted paragraph? If the answer is "yes, and we are working on it", I'll just take my fingers off the keyboard and refrain from commenting on the (weekly) mortar topics--hey, I see another one now to look in on.

Wait a bit and see whether the mortar retargetting bug getting fixed brings the game's light mortar performance more into line with what you're expecting; that "single 60mm eviscerates Battalion" result we saw reported will be a lot less possible now the mortar has to re-zero on each new target. Also remember that CM's "hard points" are only representative of "hasty" defenses, so mortars will rightly be more effective against them than against historically well-prepared slit trenches and firing pits.

targeting small quantities of infantry, unless they were extremely important. Since the small number of soldiers would likely just move if targeted, the main reason would be to deny them a specific valuable location.

The mortar retargetting bugfix will restore this behaviour, since now the first round will be unlikely to pin the target (allowing following rounds to kill them).

One other thing that might be skewing game results in favour of light mortars is the ranges at which we fight: up close the mortar scatter is much reduced, giving more lethal fire once the target is ranged in. The scatter pattern seems to have some relationship to the range, getting larger the further away the target is. If we fight at ahistorically close ranges, or if the variation in the scatter brings it unrealistically tight at close ranges, mortars will perform better than IRL.

[ForwardObserver]

The mortar retargetting bugfix will restore this behaviour, since now the first round will be unlikely to pin the target (allowing following rounds to kill them).

One other thing that might be skewing game results in favour of light mortars is the ranges at which we fight: up close the mortar scatter is much reduced, giving more lethal fire once the target is ranged in. The scatter pattern seems to have some relationship to the range, getting larger the further away the target is. If we fight at ahistorically close ranges, or if the variation in the scatter brings it unrealistically tight at close ranges, mortars will perform better than IRL.

Certainly range does affect the scattering of rounds. Nonetheless, if we were fighting on 2 x 2 km maps, either we would be closing up our mortars to max effect on targets or we would be commanding a regimental sized force (with plenty of mortars around).

Moving around the mortars in such a map would be a problem if 1) MG's lethality was higher at long ranges, and that's quite a topic of discussion, 2) the scenario provided with substantial amounts of off-map artillery assets to conduct interdiction fire missions (light or harassing over long linear targets or broad areas).

This might sound shocking, but perhaps, rather than starting from the assumption that the CMx2 model is wrong, we should consider the possibility that our assumptions are wrong regarding the US 60mm light mortars and their role in the WW2 battlefields of Europe.

I haven't any hands on experience with 60mm-like mortars , I have no idea of what contemporary militaries use them to look for that info on the Net and there's very few living veterans who can have first hand recollections about their effectiveness (or uselessness).

The only - and quite notorious - depiction of mortar crews in the media is The Pacific HBO series. I quite remember the Peleliu and Okinawa stories depicted there. And that video of the Lybian civil war, which was quite telling.

So, if the model is right, what are we doing wrong? Or, in other words, given the ability CMx2 UI grants us to control our pixeltruppen and the TacAI, can we do things differently?

One odd thing I've observed is that troops, when under fire, have this tendency to curl up into fetal position, regardless of their experience and motivation. And when they look for cover they do it crawling (the Slow commands that appear frequently at the end of a WEGO 60 secs segment replay). That strikes me as a particularly bad idea when under mortar area fire.

[Paper Tiger]

This might sound shocking, but perhaps, rather than starting from the assumption that the CMx2 model is wrong, we should consider the possibility that our assumptions are wrong regarding the US 60mm light mortars and their role in the WW2 battlefields of Europe.

Not shocking at all. I think they've got the mortars modelled accurately enough. What is out of kilter is the way the TacAI moves its units and reacts to mortar/artillery fire. I think some fudging of the lethality of mortars is required to offset the Tac AI's inability to react appropriately. This has already been done for tanks firing on the move. Because the Tac AI can't perform short halt -fire, we have overly accurate firing while on the move to simulate the short halt. I'd be happy if mortars or artillery suppressed more but killed less. More suppression and reduced lethality. Maybe even link lethality to the target unit's experience. The higher the experience the greater and more rapid the suppression will be while Green and Conscripts get killed more frequently. I doubt that this will happen though.

[JasonC]

"If we fight at ahistorically close ranges, or if the variation in the scatter brings it unrealistically tight at close ranges, mortars will perform better than IRL."

At unhistorically short ranges in real life, mortars in direct lay get suppressed by enemy small arms fire. At short range fired indirect, they have the usual correction problems. The accuracy of a 60mm mortar in direct lay at 200 meters is not going to exceed the accuracy in direct lay of a K98 rifle at 200 meters, which is about an inch and a half.

But CM correctly notices that the theoretical accuracy of a rifle on a firing range does not translate into every shot landing within 2 inches of its intended point of aim at 200 meters. Applying a completely different principle to the light mortars and their accuracy, than is used for small arms and their accuracy, results in falsified tactics, in which the mortar crew can fire with extreme precision at infantry that can see them and fire back, at close-in ranges, without doing a darn thing.

The other point I think CM still doesn't have right in mortar fire or to a lesser extent FO fire, is the true role of corrections and the limitations they face, from shot variation hiding the true point of aim from the operator.

It is easily about the best established OR result ever, that calling additional corrections once already inside the 50% dispersion radius, results in a higher not a lower average dispersion of the shots around the target. About double, in fact. Chasing random shot to shot variations does not home in on the target. It smears out the fall of shot over twice the area. It only homes when the size of the correction is twice the average shot to shot dispersion or so. When the two are equal - the correction and the random range error - you can fire forever, and correcting from shot to shot will not help, it will hurt. Technically, continuing to call corrections once inside the 50% zone of the weapon itself creates a driven oscillator feedback system. Which amplifies noise instead of averaging it away.

This is why all the actual firing procedures tell the operator to fire for effect as soon as they have an over and an under, and *not* to keep calling corrections until they get a direct hit. And if they did get a direct hit, it is vastly more likely the point of aim is still incorrect and the random spread just happened to put that one round there, than that the point of aim is actually correct at that point.

Finally, the reason why 81mm mortars and up are highly effective weapon systems is, even taking into account all of their above, it doesn't matter that the shells are landing 25 yards from the point of aim. Because their casualty radius against a standing man is at least as big as their random error. The reason light mortars are not highly effective weapon systems - and they emphatically are not, in the real world, either in WW II or since - is this isn't the case for those smaller rounds.

[DavidFields]

JasonC: "At unhistorically short ranges in real life, mortars in direct lay get suppressed by enemy small arms fire."

Yes, it is unclear how mortars can direct fire from under 200m, as is currently modeled, without being obliterated by almost anything they are firing at. I think it is a collection of decisions that allow this to happen: rapid deployment and targeting times, plus some spotting algorithms.

JasonC: "the reason why 81mm mortars and up are highly effective weapon systems is"

Not glorifying anyone--I really don't--but the most effective weapon systems early war, I contend, would be the German HMG and the 81mm mortar (I also like the MkIV tank in that mix). Or, in general, the German Company.

By 1944, that may not have been the case, and one could discuss this extensively, including why the change.

But this issue, and the issue of the light mortars, becomes more important, I think, as the series goes to earlier years, as we are seeing with CMFI, and when we get to, I hope soon, the Baltics in 1941.

As to the poster who said, in effect, maybe how the light mortars are modeled in CMFI is correct and we just need to adjust to it (I don't want to lose my Quick Reply response and look for that comment), I, respectfully, don't think so. It is possible we are going to rewrite history, and it makes me wonder what other things I thought I knew about warfare years ago is mis-fabricated through a modern lens.

[womble]

Yes, it is unclear how mortars can direct fire from under 200m, as is currently modeled, without being obliterated by almost anything they are firing at. I think it is a collection of decisions that allow this to happen: rapid deployment and targeting times, plus some spotting algorithms.

Indeed, and probably the most important bit of that algorithm (now that the insta-range bug is stomped) is the God view of the player: you can have a mortar team rock up behind some cover and drop area fire where you know the enemy are without them having to spot anything at all; they just need LOF to a handy action spot. The elements facing that cover don't have much chance of spotting the mortar until it starts firing, and by then it's posibly too late if the team is any good; at short range, Elite teams seem to drop the first ranging round pretty near the intended aim point. I don't know whether the team having to futz around for a while setting up would mean they get spotted earlier behind good concealment.

[Steiner14]

@JasonC

Brilliant.

I hope that BFC finally will listen.

[c3k]

At unhistorically short ranges in real life, mortars in direct lay get suppressed by enemy small arms fire. At short range fired indirect, they have the usual correction problems. The accuracy of a 60mm mortar in direct lay at 200 meters is not going to exceed the accuracy in direct lay of a K98 rifle at 200 meters, which is about an inch and a half.

But CM correctly notices that the theoretical accuracy of a rifle on a firing range does not translate into every shot landing within 2 inches of its intended point of aim at 200 meters. Applying a completely different principle to the light mortars and their accuracy, than is used for small arms and their accuracy, results in falsified tactics, in which the mortar crew can fire with extreme precision at infantry that can see them and fire back, at close-in ranges, without doing a darn thing.

Partially quoted from upstream, my bold added.

Theoretical, and practice range, accuracy is, indeed, orders of magnitude better than combat accuracy.

While I agree with the thrust of this thread, what is it about small mortars which will increase their dispersion in real life combat? Is it purely range estimation? Bent fins? Non-level sights? Bases which shift?

With a rifle it is easy: adrenaline, fear, stress, hurried shooting, all produce misses.

Why should a bipod and base, sighted in, "heavy" weapon miss its aimpoint in combat?

[Streety]

There's play in the mortar tube (i.e. the ammo is not a 100% perfectly tight fit into the tube), which widens the trajectory cone, and no two rounds have the exact same shape, weight, charge or speed and intensity of ignition (not down to the nearest microgram, or millisecond, etc). Same goes for fins - even those which aren't bent. Which each all have a tiny impact on trajectory but which added together over a distance can have a small (sometimes randomly off-setting and sometimes randomly cumulative) effect. Then there's the temperature of the firing tube (which will vary and effect the above factors), and you probably have chaos theory with regard to exhaust gasses as they interact with the fins. The ground can move a tiny amount. Then there's the weather/wind which is not constant (even on a calm-ish day).... oh lots of little things like that can all play a part.

[newlife]

There's also setting up at breakneck speeds, bumping into the mortar in the process of spotting and hitting the dirt, or perhaps the ground is not 100% ideal. There's still adrenaline and fear involved during ranging and sighting (almost the horror movie style fumbling with the car keys as the big meanie gets closer). May still be better than a rifle, but there still variables.

[womble]

There's play in the mortar tube (i.e. the ammo is not a 100% perfectly tight fit into the tube), which widens the trajectory cone, and no two rounds have the exact same shape, weight, charge or speed and intensity of ignition (not down to the nearest microgram, or millisecond, etc). Same goes for fins - even those which aren't bent. Which each all have a tiny impact on trajectory but which added together over a distance can have a small (sometimes randomly off-setting and sometimes randomly cumulative) effect. Then there's the temperature of the firing tube (which will vary and effect the above factors), and you probably have chaos theory with regard to exhaust gasses as they interact with the fins. The ground can move a tiny amount. Then there's the weather/wind which is not constant (even on a calm-ish day).... oh lots of little things like that can all play a part.

All of which apply on the range. Newlife has more relevant factors for differences between range performance of heavy weapons and their performance on the field of battle.

[Michael Emrys]

I would expect wind to be larger factor for mortar rounds than for other artillery due to the slower velocity of the round.

Michael

[John Kettler]

Michael Emrys,

Please see my posts 143 and 144 in this thread, where I went into considerable detail on error sources for mortars vs. field artillery, to include wind, wind exposure times and weathercocking.

http://www.battlefront.com/community/showthread.php?t=106208&page=15

Regards,

John Kettler

[DavidFields]

JK: "Returning to the direct lay mortar problem, I feel I should note the direct lay mortar has a perfectly legitimate responsiveness advantage over the same weapon, at the same elevation and charge, which is fired in indirect lay.

Nor does the direct lay mortar gunner have to worry about orientation relative to the GTL (Gun Target Line) or axis of fire, being its origin, thus not having to consider offset angles. With the target under direct observation, there is less likelihood of inducing more MPI error while moving the MPI to the DMPI. Adding an FO/FOO to the mix, plus an FDC (Fire Direction Center) only increases the potential error budget."

Re-reading these spectacular posts.

They are even better the second time around.

I will only add the following: yes, direct fire mortars would be more responsive, and correct fire more rapidly--avoiding another communication delay/error.

But they were tremendously vulnerable. No gun shields, like some AT/IG weapons. If they are not in a prepared position (sort of a locally indirect method--where the mortar is below ground level and someone in the local group is spotting),they are above ground, making noise and smoke, with no defense. They should (not because of play-balancing, but because of the reality of placing a tube in the open an making noise is different than the other infantry) have a tremendous "spotted" bonus. That would force them, naturally and realistically, into indirect fire.

[John Kettler]

Rankorian,

Thanks for appreciating my carefully crafted argument! I agree that a mortar in direct lay is considerably more vulnerable than one firing in indirect lay, but a small mortar (2-inch, 50mm, 60mm for our purposes) doesn't have much of a firing signature, what with the muzzle blast being more vertical than horizontal and the powder charge weak, compared to an equivalent size direct fire weapon. I would argue its principal signature is acoustic, rather than visual.

As I noted before, the Hollywood portrayal isn't even close to the reality. Unseasoned troops may not even notice the sound of firing, and mortar bombs don't shriek as they come in. Rather, it's a soft fluttering sound. So, to someone not paying close attention, the first indication of trouble is likely to be the first round's detonation. Seasoned troops, by contrast, will have learned that the Toonk! of firing and its direction relative to them denotes immediate trouble and will hit the deck forthwith.

What would attract hostile attention, I think, is the distinctive pattern of movement associated with serving a mortar, less so in the case of the trigger-fired 2-inch and 5cm. It would appear the AI is not "trained" to notice and respond to this, whereas it IS trained to spot and respond to AT teams. Perhaps an AI tweak would make mortars a near instant target, in turn resulting in casualties bad enough to force a return to firing from defilade? Crew served weapons are natural high priority targets, and mortars definitely fall into that category. Snipers love such targets.

Regards,

John Kettler

[JasonC]

"the Hollywood portrayal isn't even close to the reality"

Except for the opening combat scene in "Cross of Iron". That shows what indirect fire from a mortar position really sounds like, and what happens when small arms meet mortarmen at small arms range. Hint, the mortars aren't going to win that one...

OK, the knife parts are pure hollywood. But the mortars are making the right sounds, and surprise, grenades, and point blank small arms fire are real enough. Not an action movie shootout - more like murder.

[JasonC]

More on mortar effectiveness in real life.

The following link shows the US army field manual on tactical use of mortars in combat. It has an appendix, B, on planning for the fire effects of mortars, against various targets. Some rely on tech more modern than WW II (proximity fuzes for airbursts, improved HE performance, etc). Read the figures for the less effective rounds of each caliber without proximity fuzes, to get the WW II era fire effects of these weapons.

http://www.globalsecurity.org/military/library/policy/army/fm/7-90/index.html

See in particular Appendix B on target effects planning for mortar fire.

http://www.globalsecurity.org/military/library/policy/army/fm/7-90/Appb.htm

Note that two sets of figures are given for 60mm mortars, the larger effective radius involving recent, improved rounds. The smaller radii for the previous standard ammunition are more relevant for the WW II performance of 60mm mortars. Also note that the effectiveness claimed and rounds per fire mission vs various targets assumes the availability of airbursts from modern proximity fuses, not available in WW II (only late 44 for western Allies div arty). See the table toward the end on area affected by each round of the various calibers to estimate the loss from not having those, and trying to make it up on volume, instead. (Basically, for the smallest calibers in particular, without airburst fuzes you lose 50-60% of the area affected or need to fire 2 to 2.5 times as much for the same impact).

Briefly, the casualty radius of the 60mm mortar round vs a standing man is about 20 meters. For the 81mm, it is more like twice that (35 meters, 40 with improved modern ammo but 35 for WW II).

The target being prone cuts the fire effect in half, and the target seeking cover in addition, can cut it by a factor of 10, compared to standing and unalerted (up to 5 times better than just being prone).

Fighting positions are a huge improvement over even being prone in the open. The manuals stated danger area from a single 60mm mortar round, without proximity fuze, against men crouching low in uncovered fighting positions, is 1 square meter. For the 81mm, it is all of 5 square meters. Basically you need a direct hit, and without it light and medium mortars can certainly suppress men heads down in foxhole cover, but they are not going to physically injure them. The illustrations (see B-8) show why, if anyone needs it explained, and also why airbursts via proximity fuzes make overhead cover much more important these days.

Note that just being alerted and seeking cover will lower the affected area by 2-5 times the prone figures, but that still leaves another factor of 10 improvement for being heads down in a foxhole.

There is a reason everyone dug foxholes in WW II...

Also note the following comment about soft ground - "One foot of soft ground, mud, or sand, or 3 feet of snow can reduce the effectiveness of surface-burst HE rounds by up to 80 percent. Light mortar rounds can land close (within a few yards) to a target on this type ground and still have no affect (sic)."

It is also worth noticing that no target below platoon size is even mentioned in the document. That is the proper sized target for light and medium mortars, because shot pattern won't be appreciably bigger than the full target size. When instead the area of the target is significantly less than that presented by a platoon, much of the firepower thrown will just be wasted. Basically, for small targets you'd have to divide the fire effect by the ratio of the actual target's size to that of a single infantry platoon in typical deployments.

It is also noteworthy that there is nothing in the manuals about any vastly increased effectiveness of mortar fire in direct lay compared to called indirect fires. There is plenty on use of fire direction centers or not, but all of it focused on the need for speed vs planning preparedness, none of it is about 2 to 5 fold improvements in accuracy being available if the gunner himself can see the target, or anything of the kind. The way to improve fire effects is to catch the enemy in the open and, if available, use airburst fuzes, not to correct the fall of shot to direct hits. (Also notice that they regard mortar fire vs even light armor as ineffective, beyond buttoning them up).

[womble]

Briefly...

Phew. Thanks for the summary!

The target being prone cuts the fire effect in half, and the target seeking cover in addition, can cut it by a factor of 10, compared to standing and unalerted (up to 5 times better than just being prone).

[snip]

Note that just being alerted and seeking cover will lower the affected area by 2-5 times the prone figures, but that still leaves another factor of 10 improvement for being heads down in a foxhole.

This suggests a couple of things to me:

1) the TacAI reaction to detected incoming mortar fire (the ranging rounds, in the case of direct lay) is the correct one: get down and seek cover, preferably a foxhole.

2) if the protection factor for the various self-defense behaviours are properly accounted for, we'll be getting much closer to "realistic" performance for light and medium mortars in both modes of fire.

...soft ground...

People have mentioned this factor before. I don't know if anyone's actually thrown up any test results here to show whether it's considered in the burst algorithms. I know it doesn't feel like artillery has any less effect on troops slogging through marsh...

It is also worth noticing that no target below platoon size is even mentioned in the document. That is the proper sized target for light and medium mortars, because shot pattern won't be appreciably bigger than the full target size. When instead the area of the target is significantly less than that presented by a platoon, much of the firepower thrown will just be wasted.

I don't expect the manual meant a great deal to the PBI pinned down by an MG nest... They would only peripherally care that only half or a quarter of the lobbed bombs would be anywhere near their target, so long as some of them got close enough to have some effect.

It is also noteworthy that there is nothing in the manuals about any vastly increased effectiveness of mortar fire in direct lay compared to called indirect fires....none of it is about 2 to 5 fold improvements in accuracy being available if the gunner himself can see the target...

To be fair, I don't think I've seen 2 to fivefold improvements in accuracy for direct lay at similar ranges to the ranges indirect missions get fired at. The decreased scatter radius is pretty much (as far as I can see so far - still testing) proportional to the decreased range. It occurs to me that this progression might well be a mistaken assumption (or unfortunate abstraction) in the game calculations, since the high parabolas of mortar shells even at short range and low charge increment expose them to a lot of windage, and once you're down to one propellant charge increment (so, what? a quarter of max range for a 60mm bomb with 4 increments available?) any recoil effects, the muzzle velocity and flight time will be the same for all shots, so the scatter shouldn't change much.

(Also notice that they regard mortar fire vs even light armor as ineffective, beyond buttoning them up).

I wouldn't fire mortars at anything that didn't have an open top, in CM, with the intent of causing casualties. A decent thwack with an 81mm mission will definitely immobilise pretty much any armour in the game, though. This always seemed overmodelled to me.