British Field Artillery Undermodelled?

[JasonC]

Actually, from the data on the site offered, it is the US that is being systematically undermodeled in blast numbers. The 25s may well be undermodeled in ROF, but they are if anything overmodeled in blast rating.

The table says the 25-lber was only 7% HE by weight, thus only 1 3/4 lbs of HE, or around 0.8 kg per shell. The US 105mm was 14.8% HE by weight, with a heavier shell, thus 2.2kg per shell. Leaving aside the fact that the US used pure TNT more often, while others often used amatol mixes with less explosive power, that means a US 105 had 2.75 times the bursting charge of a 25-lb round. But the blast ratings are only in the ratio 1.3 times.

Even if you assume the blast ratings should only go as the square root of the charge size (the system the UK used during the war, to convert to "25-lb equivalents"), you'd expect the US 105 to have 100 blast, or the UK 25-lber to have only around 45, or a bit of both.

Incidentally, the size of the bursting charge in the 25-lber is not much larger than that in US 75mm HE. The gun was really closer to a 75mm than to a 105mm in its HE capabilities. CM puts its blast rating exactly between the two of them (39+77/2=58) - and incidentally, above the blast rating of a German 88mm.

The 4.5" is also noticably overmodeled, with its 125 blast rating. In fact, the shell was only 7% HE burster again, and the HE load was thus lower than in a US 105 shell. But CM gives it 1.6 times the blast rating. Similarly, the 5.5" had only 2/3rds to 3/4ths of the HE burster of a US 155mm, but is given the same blast rating.

Changing 25s to 20 rounds per minute would be fine by me (each module would still be 4 guns, so you'd need 2 to simulate 8 firing simultaneously). But a blast of 45-50 each would be more reasonable. The 4.5" does not deserve what is has, and should probably get more like 85 blast at most. Naturally the cost would be adjusted along with the blast ratings. 5.5" probably deserve more like 150-175.

The current blast rating for 105s is about in line with the others for the *German* 105mm, but the US shell had a larger bursting charge - 60% larger. It does not deserve only the same blast rating. It should be more like 100, with the cost more like that of the VT battery now.

One man's opinions...

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by John Kettler:

I don't have the citation handy, but according to an account I read Germans shelled by the 25 pdr. were so demoralized by its ROF that they thought it was some sort of automatically loaded weapon. They couldn't believe conventional artillery could possibly fire that fast.<HR></BLOCKQUOTE>

I wonder how much of that was due to the 25 pdrs being allocated in 6 gun batteries as opposed to the 4 in German and American batteries. That's in addition to the slightly higher ROF of the 25 pdr.

Michael

[JonS]

8 gun btys Michael. Otherwise ... the same thought had occured to me.

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JonS:

8 gun btys Michael.<HR></BLOCKQUOTE>

My mistake.

Michael

[Vanir Ausf B]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

Similarly, the 5.5" had only 2/3rds to 3/4ths of the HE burster of a US 155mm, but is given the same blast rating.<HR></BLOCKQUOTE>

Not the same. The 5.5 has a BR of 208 compared to the 155s 198.

Which is something I have always wondered about, as the 5.5 is only 140mm...

[JasonC]

You know, it is almost exactly as though a weapon gets 1.4 times the blast rating (or up by a factor of the square root of 2) just for being British. Thus, 208 / 1.4 = 149, which is 3/4 what a US 155 gets; 125/1.4 = 89, which is about what a 4.5" deserves compared to a German 105, and 59/1.4 = 42, which is what a 25-lber deserves compared to a US 75mm, just going by burster weight. The same relationship exists between a 3" mortar round and an 81mm (26/1.4 = 19) - though supposedly with more justification there, as the standard 3" bomb weighed 10 lbs rather than 7 lb.

Perhaps a 1.4 factor that is reasonable for the 3" mortar was magically granted to everything thrown by a tea-drinker?

[Simon Fox]

<BLOCKQUOTE>quote:</font><HR>just going by burster weight<HR></BLOCKQUOTE>Which IIRC BTS did not.

[JasonC]

Duh. It gives anything UK a 1.4 times blast multiplier, as I already said. The question is "why?"

[Vanir Ausf B]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

Duh. It gives anything UK a 1.4 times blast multiplier, as I already said. The question is "why?"<HR></BLOCKQUOTE>

I'm going to go out on a limb here and say that it may be because of different materials used in US and UK shell casings.

I can't find where I read it, but I remember reading that the British did some tests that showed cast iron casings produced far more fragments upon bursting than steel casings (about twice as many IIRC). The downside to cast iron shells was that they had a shorter range than steel shells because of the weaker material.

So, if the Brits used cast iron casings and the US used steel, that could explain the difference. However, I can't find a source that states whether or not this is true.

Of course, none of this explains the 25 lber ROF.

[Simon Fox]

Well I am not clear on how you derive your mysterious 1.4 factor. It may well be that some of the blast ratings are "off", though I don't think that applies to the 3in mortar which by all accounts was substantially better than the 81mm, but your 1.4 "fudge" factor just confuses the issue IMO. It is possible that BTS used some of the Brit ordinance tests which used more than just blast to account for effectiveness but I am only speculating.

From what I can gather most Brit 25pdr HE was TNT filled. The US did have non-TNT filled 105mm HE but I am not sure how common that was.

The Brit choice of 25pdr (88mm) rather than the 105mm used by other nations in their field arty has a lot to do with their artillery doctrine which could be considered as a "more bangs" approach. Thus supposedly having more tubes in a battery firing at a faster rate put down more rounds in a short time period. Unfortunately with the current rate of fire it is hard to acheive. You may be right that the 25pdr blast is a little high and should be closer to the 75mm than the 105mm rating. If you could get 20rounds/min out of an FO instead of the current 12 I think it would be an acceptable trade off for a lower blast rating.

[Spook]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Germanboy:

All references by the Germans at the receiving end are of stunned awe. The system was perfected later on in the war. It is quite significant that the only two major defeats of sizeable Commonwealth troops that I can immediately think of are 1st Airborne (out of reach of XXX Corps arty) and Worthington Force (arty called on wrong location, due to inability to read maps). Otherwise breakthrough after breakthrough, right from day one in Normandy stopped in artillery fire (21st Panzer at the beaches, 12th SS NW of Caen, 7th AD after Villers-Bocage).

<HR></BLOCKQUOTE>

In due respect, Andreas, I find poor connectivity in the above statement to the issue of artillery fire rate. Because it wasn't always "breakthrough after breakthrough," when considering actions like Epsom, Hill 112, Goodwood, the Reichswald, to name but a few examples. Not necessarily defeats, but not out-and-out lightning-bolt breakthroughs either.

Artillery firepower & fire control were crucial, but not always the defining factors for battles won & lost when taken on a case-by-case basis.

I am, however, of the general notion that UK/Commonwealth artillery fire direction was typically superb, perhaps better than even for the US when averaged out. And given that CM does link firing rates to specific gun calibers, I also concur with Simon that the 25-lbr's firing rate seems too low.

Hopefully, when the West Front is revisited with CM II, both firing rates and "blast effects" (Jason's issue) will be given due review for possible revisions.

(PS: XXX Corps did get some artillery up close enough to support the British 1st Airborne, just before the evacuation. It wasn't enough to turn the tide, but enough to keep the pocket from collapsing too early.)

[Andreas]

Spook, I agree about the connectivity - it was Babra who came up with the idea that the low ROF somehow simulated bad UK practice, so there is actually zero connectivity there.

The breakthroughs I talked about were German initial breakthroughs that died in a rain of shells. It was different when the Commonwealth attacked, especially in Normandy. Then artillery did not play such an important role, since it is much less useful against dug-in defense. Later this changed, according to my reading, with the introduction of the Pepperpots, that sometimes helped crush defenses, and at other times seem to have been much less successful.

[Spook]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Germanboy:

The breakthroughs I talked about were German initial breakthroughs that died in a rain of shells. <HR></BLOCKQUOTE>

Ah. Duly corrected, then.

[JasonC]

Yes, the British used weaker, softer metal casing for their shells. They didn't do so for the blast effects, though, they did it for reasons of expense and materials economy. As a result, the casings had to be thicker to sustain the force of firing, which led to smaller charge weights for the same weight of shell. Thus the 25 and 4.5" are only 7% HE by weight, vs. more like 15% for US 105 rounds.

But the approximation of shell effectiveness as the square root of the charge weight was the one actually used by the British themselves during the war. They used it to "translate" into "25-lber equivalents", to determine volumes of fire needed for a given area to achieve a given level of effect. They did not regard their one shells are 1.4 times as effective as that, because of casings or for any other reason.

The US had far greater supplies of TNT available than any other combatant, which is why it made less use of amatol style mixtures. The Germans made the greatest use of such mixtures. Basically it stretched the available TNT. You'd get 80% of the blast effect from 60% of the explosives expense. But it did mean the destructiveness of the same weight of HE would typically be lower for German rounds, highest for most US rounds.

I have seen no sign in the blast figures given that BTS took full info on charge weights into account. For instances, the bursting charges of typical 81mm mortar rounds were roughly the same as those of 75mm HE, or at best around 4/3s as high for the 75mm. BTS gives them double, which closely tracks shell weight rather than bursting charge. The relation between 4.5" and 105 also exactly tracks overall shell weight; so does the ratio between Brit 25 lber and US and German 105s. BTS is primarily using shell weight as a proxy for blast, therefore.

Which means it favors shells with low ratios of burster to weight over those with high ones, compared to the relationship artillerists of the day used themselves to estimate relative artillery effectiveness. Which favors the Brits and penalizes the Americans.

[Michael Emrys]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

I have seen no sign in the blast figures given that BTS took full info on charge weights into account. For instances, the bursting charges of typical 81mm mortar rounds were roughly the same as those of 75mm HE, or at best around 4/3s as high for the 75mm. BTS gives them double, which closely tracks shell weight rather than bursting charge. The relation between 4.5" and 105 also exactly tracks overall shell weight; so does the ratio between Brit 25 lber and US and German 105s. BTS is primarily using shell weight as a proxy for blast, therefore.

Which means it favors shells with low ratios of burster to weight over those with high ones, compared to the relationship artillerists of the day used themselves to estimate relative artillery effectiveness. Which favors the Brits and penalizes the Americans.<HR></BLOCKQUOTE>

I am just speculating here, but it is conceivable that when this part of the program was written, BTS may have only had data on shell weight and not on charge weight or other relevent data for all shells used in the game. They might have also opted for a simplification on this issue.

Michael

[JonS]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JasonC:

... Perhaps a 1.4 factor that is reasonable ... was magically granted to everything thrown by a tea-drinker?<HR></BLOCKQUOTE>

Ah, now this actually makes sense.

My source?

Goscinny and Uderzo "Asterix in Britain", 1966

[JasonC]

Very likely. The overall shell weights are easily found. Nuances of shell composition and effectiveness probably seemed far out into grogland. Would mean several weapons are undermodeled, and others overmodeled. It would also be a nice thing to see improved for CM2...

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Simon Fox:

The Brit choice of 25pdr (88mm) rather than the 105mm used by other nations in their field arty has a lot to do with their artillery doctrine which could be considered as a "more bangs" approach.<HR></BLOCKQUOTE>

That's a curious statement. Care to provide a cite?

<BLOCKQUOTE>quote:</font><HR>"In Britain, the question of a replacement for the 18-pounder gun and the 4.5-inch howitzer had been under consideration for many years. Such agreement as there was seemed to favour a single weapon that would be capable of carrying out the roles of both the relatively flat-trajectory, high-velocity gun and the high-trajectory, low-velocity howitzer. Again, there seemed to be some sort of agreement that the calibre should be somewhat more than 4 inches, with a shell weighing approximately 30 pounds. As it turned out, both the Germans and the Americans came to rather similar conclusions; the only difference was that they put their new 105-millimere field pieces into production.

Technical difficulties were not the only problems British gun designers had to cope with; equally significant were the pervasive effects of economic depression and disarmament. A few experimental models of potential replacements were built, but it was clear that the politicians would never agree to the wholesale re-equipment of the Royal Artillery as their predecessors had done after the South African War. The only acceptable design would be one that, in some way or other, utilized the vast existing stocks of 18-pounders. These guns already had a calibre of 3.3 inches: with high-quality steel they could be more thinly relined to yield a calibre of 3.45 inches and thus permit the firing of a 25-pound shell."

Canada's Guns - An Illustrated History of Artillery

Leslie W.C.S. Barnes

Canadian War Museum Historical Production No. 15<HR></BLOCKQUOTE>

Seems to me the adoption of the 25-pdr was purely economic.

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Germanboy:

it was Babra who came up with the idea that the low ROF somehow simulated bad UK practice, so there is actually zero connectivity there.<HR></BLOCKQUOTE>

Do you just make this stuff up as you go along? That isn't even remotely what I said.

[Michael Dorosh]

Wow. I don't even remotely miss these kinds of discussions. Babs is the first one on this page to provide a reference. Kind of makes the other nonsense seem more like what it is.

See you boys in full force come Saturday when Borden turns me loose. Babra, your Southern Ontario weather sucks. I hate to say it, but I am almost glad that poor bastard in Barrie died - if it hadn't of happened, they would have been drilling us outside in 45 degree Celsius weather until it was one of us that died. As it is, that poor baker got a bunch of our parades cancelled.

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael Dorosh:

...if it hadn't of happened, they would have been drilling us outside in 45 degree Celsius weather until it was one of us that died. <HR></BLOCKQUOTE>

Hehe. Try a route march through the Negev in full battle kit some time

[Andreas]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Babra:

Do you just make this stuff up as you go along? That isn't even remotely what I said.<HR></BLOCKQUOTE>

Nope, no making up. I must have misunderstood this one then:

<BLOCKQUOTE>quote:</font><HR>Originally posted by Babra:

Combined arms doctrine was quite weak among the Commonwealth forces, in some cases (during attacks) forward units had no artillery support at all after the initial push-off, despite an abundance of ready reserves.

If you put the limitations of the 25 pdrs into that light, it's an easier pill to swallow.<HR></BLOCKQUOTE>

Apologies if I misunderstood it, but to me that looked very much like 'Yeah, ROF maybe low, but hey, they couldn't do combined arms anyway, so see it as part of the simulation'.

[mensch]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Michael Dorosh:

Borden turns me loose. <HR></BLOCKQUOTE>

hmm damn, give me your Commanders phone number I'll help you stay a little longer if you want, it's a great place no?

<BLOCKQUOTE>quote:</font><HR>they would have been drilling us outside in 45 degree Celsius weather until it was one of us that died.<HR></BLOCKQUOTE>

ya when we were there the passout rate was about 1 every hour, but it didn't matter the Drill officer was a nob and made us carry the lucky bastards to the shade give them water and make sure they don't die from heat stroke*

*we had to make sure they lived so they get Firepicket duty and some other crapy duties for being wet towels.

<BLOCKQUOTE>quote:</font><HR> As it is, that poor baker got a bunch of our parades cancelled. <HR></BLOCKQUOTE>

bastard, that never happened to us!! if we were not baking in the sun with our.. get this Black berets (armour corp thought it would look cool I guess, all it did was speed up the process of cooking tankers Brains) or Marching around and see how much water our bodies could absorb in the rain before turning into a wrinkly pudgy mess which then the NCO could yell at us cuz we look like some sea sponges in uniform.

Did you get the chance to go out in the "wastelands" and try to dig trenches in sand? (sick joke from the NCO's mefinks)

[ 08-15-2001: Message edited by: mensch ]

[Fieldmarshall]

Mensch....did you find the book?--(Resource on 1945 battles)

--Fieldmarshall

[Guest Babra]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Germanboy:

Apologies if I misunderstood it, but to me that looked very much like 'Yeah, ROF maybe low, but hey, they couldn't do combined arms anyway, so see it as part of the simulation'.<HR></BLOCKQUOTE>

Now you're at least close. Your previous statement that one was a 'simulation' of the other was just tripe. And I didn't say they "couldn't do combined arms". They clearly could. I said it was weak, and then only on attacks. You came back citing many GERMAN attacks being broken up by said arty. If you diagree with something, at least know what you're disagreeing with.