Brummbars vs. 150s

[PantherG]

Brummbar guns are 150 L/12s and have a blast of 248. Normal 150 L/11s have a blast of 303. Why would adding another 6 inches to the barrel lower its blast? Or are they just different guns in the first place(they have the same HC penetration)? :confused:

[bab]

Maybe the faster round of the longer gun goes deeper underground, slightly reducing the explosion effect?

[PantherG]

Interesting idea. Does the L/12 have a higher velocity than the L/11 (obviously it does, but significantly enough to reduce the blast be 55 points!)?

[Guest Mike]

For starters it's not the same weapon as the 150mm IG - it's a lightened development of it - the 150mm StuH 43 L/12 gun.

I think the muzzle velocity thing is a red herring as far as blast ratings go - a minor detail jumped upon by over zealous grogs picking their nits!!

Rather it the answ4er probably lies in somthing much more mundane - like the ammo used.

The HE round for the tank gun weighed up to 81 lbs, which seems a little light for a 150mm gun, so that's more likely the answer to the blast rating - I don't have any details on the infantry gun round to hand but I do have some at home and will post them tonight if no-one else has done so by then.

[ December 15, 2002, 07:35 PM: Message edited by: Mike ]

[RMC]

Well, a quick check of my source says both the 15cm sIG 33 (L/11) and the 15cm StuH 43 (L/12) had the sme MV for the HEAT round they used.

Another says the MV for the sIG was 240m/s for HE and 280 m/s for HEAT.

I had to look in a third source to see that the MV for the StuH is rated at 241 M/s for HE.

I don't think that 1 m/s would account for a 18% drop in explosive power. There must be something more. They shared the same HEAT projectile, but they could have very different HE projectiles.

[bab]

It was just a quick idea...

[Brightblade]

Originally posted by PantherG:

Brummbar guns are 150 L/12s and have a blast of 248. Normal 150 L/11s have a blast of 303.

What exactly are you talking about? Any German 150mm gun in CMBB has a blast of 248, with the exception of the Hummel which has 303. And the Hummel has a 150L30 gun, which might explain the higher blast rate. But maybe they used another sort of ammuniton which would also explain the much higher muzzle velocity (375 for HE, 460 for HEAT), in addition to the longer barrel of course. Though maybe they used the same ammo but a higher propelling charge.

[ December 16, 2002, 05:15 AM: Message edited by: Brightblade ]

[Olle Petersson]

Originally posted by Brightblade:

What exactly are you talking about? Any German 150mm gun in CMBB has a blast of 248, with the exception of the Hummel which has 303. ...

Err, no?

Did a quick check:

- On map sIG 33 (150L11), towed and SP versions:

Blast 248

- On map Brummbär (150L12):

Blast 248

- Regimental 15cm arty spotter (2x sIG 33):

Blast 299

- Divisional 15cm arty spotter (4x sFH 18 (150L30)):

Blast 299

- On map SP sFH 18 (Hummel):

Blast 303

It's beyond me why there's such a different in blast rating depending on if the howitzer is on or off map.

sIG 33 gain 20% by being off map, while sFH 18 gain 3% by being on map!

Cheers

Olle

[StellarRat]

Well, they may have given the off map arty a better rating because the shell is coming down nearly straight down (almost 90 degrees to the ground.) This gives it a much better fragmentation pattern compared to a flat trajectory shell (on map.) Why Hummel is better I don't know. Perhaps it uses different ammo (thinner casing?) One thing to keep in mind about on map vs. off map is that the on map is a lot more accurate and therefore likely to do more damage to a particular unit even if the blast is a bit lower.

[Shosties]

Perhaps the shells issued for the Brummbar were shorter than the ones fired by the infantry gun, and being shorter they held less explosive filler. Making the shells shorter would make them handier within an assault gun and allow more to be carried. Well, that's my idea anyway. Is there a German arty ammo grog in the house?

[Redwolf]

People should also remember that the actual explosion in CM has more parameters to it than the one blast value. The blast value as given to the player is just a summary of a more complex model.

I didn't make extensive CMBB testing yet, but for CMBO do the following: Set up some Amis in foxholes and then blast the foxholes with either 150mm infantry guns or Hummels. Although the infantry gun has a lower blast value (164) than the Hummel (200), the infantry gun drives the squads out of their foxholes faster. I was able to reproduce that reliably.

So I guess someone should set up tests of these CMBB guns against different targets (infantry in foxholes, infantry out of foxholes, buildings, airplanes) and see who's stronger in what. I guess we are in for some surprises.

[Brightblade]

Originally posted by Olle Petersson:

- Regimental 15cm arty spotter (2x sIG 33):

Blast 299

First of all I want to make clear that I only meant on-map guns, but I didn´t say that in my first posting, sorry.

I very much doubt that sIG would be used for artillery purposes. Their range was very limited due to the short barrel. They were intended to support infantry with direct fire, that´s where there name comes from "schweres Infanteriegeschütz" (heavy infantry gun).

Maybe they have been used occasionally for indirect fire, the way tanks have been used for artillery purposes, but I´m very sure that they were not used in regular artillery units.

The difference between the off-map sFH 18 and the Hummel seems to be strange, but then the difference is only very small (about 1.4% depending on which value you take as base, not 3% as you said) and as redwolf said, the blast rate is an abstraction from various factors.

Maybe the off-map blast is a bit lower because it´s assumed that these shells detonate a little bit deeper in the ground than if they are fired by on-map guns. It´s a wild guess, but who knows (besides the guys from BFC, of course )?

[ December 17, 2002, 12:25 PM: Message edited by: Brightblade ]

[Stalin's Organ]

Originally posted by Olle Petersson:

- On map sIG 33 (150L11), towed and SP versions:

Blast 248

- On map Brummbär (150L12):

Blast 248

- Regimental 15cm arty spotter (2x sIG 33):

Blast 299

HE shell weight is 38kg (83.8 lbs) for the sIG 33.

I suspect if the 150mm regimental observer is supposed to represent these guns then it may be an oversight that gives them a blast of 299.

The sIG's had a range of 4700m, which is short but still gives them plenty of scope for off-table use at the scale of CMBB.

- Divisional 15cm arty spotter (4x sFH 18 (150L30)):

Blast 299

- On map SP sFH 18 (Hummel):

Blast 303

43.5kg/95.7 lb

Which explains whey the sFH 18 has a higher blast rating overall, but not why it's different on/off map of course.

[ December 17, 2002, 07:49 PM: Message edited by: Stalin's Organ ]

[Olle Petersson]

Originally posted by Brightblade:

I very much doubt that sIG would be used for artillery purposes. ... I´m very sure that they were not used in regular artillery units.

I'm likewise very sure that the typical regimental artillery was 2 towed sIG 33 and 6 towed lIG 18 (75mm).

The exception being armoured infantry regiments, that had 4 SP sIG 33 (Grille).

The regimental artillery never had any other type of large calibre gun, AFAIK.

Therefore follows that the two-tube regimental spotter controls towed IGs. They had a maximum elevation of about 70 degrees and a maximum range of about 3 miles, so indirect fire was definitely an option. (Minimum range in upper registry was less than 800m.)

... (about 1.4% depending on which value you take as base, not 3% as you said) ...

Correct! My math was a bit off by 2 a.m. ...

Cheers

Olle