On map 75mm Guns

[Erwin]

Noticed that on-map 75mm inf guns cannot be used for indirect fire in the setup phase if the spotter has no LOS to the target - unlike all offmap artillery which can be set to fire anywhere on the map regardless of spotter LOS.  Anyone know if that deliberate or a bug?

[Warts 'n' all]

5 hours ago, Erwin said:

Noticed that on-map 75mm inf guns cannot be used for indirect fire in the setup phase if the spotter has no LOS to the target - unlike all offmap artillery which can be set to fire anywhere on the map regardless of spotter LOS.  Anyone know if that deliberate or a bug?

It is not a bug. Where they can fire is governed by whether or not they are able to fire over blocking terrain.

[Erwin]

The on-map guns are positioned in an open field.  Can't see any blocking terrain.  Can only order indirect prep fire in the setup turn if the target location is in LOS of the spotter. Unable to order indirect fire anyplace else like one can with off-map arty.  Am wondering if the map is not large enuff for the on-map guns.  They are inf guns not howitzers.

Edited February 8, 2021 by Erwin

[chuckdyke]

Maybe it has to do with the trajectory of a 75 mm shell. You can have LOS but not LOF. 

[Warts 'n' all]

There have been a lot of threads about this topic, and without knowing the battle you are playing, or the map you are playing on I don't see what more help you can be given.

[Erwin]

Battle 7 of Die Letze Hoffnung campaign (not much help I imagine).  But, it makes sense that an on-map gun cannot indirect target/fire within a certain minimum range - otherwise it could target itself with indirect fire.  The on map guns therefore can only be used for direct fire (unless the map is sufficiently large).

[Warts 'n' all]

I actually fired this up as a stand-alone battle yesterday, so I am familiar with the map. And although the FO in the church can see right across the battlefield I think 300 meters was about the longest I could set an indirect mission without the infantry guns losing LOF (Keine Schusslinie). So I will just be using them in the direct fire role if the need arises.  

[mjkerner]

I fired it up the scenario and was able to call for undirect fire within 165 yards of my FO in the church tower. (The guns were in the back of the map where they were initially, I unlimbered them in place.) However, things got interesting because the gun itself appeared to be using direct fire, and its shells were hitting a building right next to the church that was in the path of the shell's trajectory to the target. 

Also, I could have sworn there was a bit in the BN manual or on the GUI itself that showed a minimum/maximum range for these infantry guns, but couldn't find anything.  They do in fact have a minimum range, just like larger mortars, but damn if I can find it. Maybe in a later manual?

[Erwin]

Not sure what scenario you are looking at.  In the one I'm referring to, the player is the attacking German and one has to capture the town with the church tower.

When the two German 75mm inf guns were unlimbered and deployed they could not be used to indirect fire in the set-up turn.  However, am thinking that it is reasonable that they could not fire indirect below a minimum range from the gun itself - ie: the guns don't have the ability to shoot near vertically like a howitzer or mortar can.  So, the range at which I was trying to preset fire in the setup turn must have been less than the minimum range.

 

 

[mjkerner]

I exploded the scenarios from the campaign a long time ago, and forgot that the de-compiler numbers them starting with "0", so I was actually testing on Battle 8. Still can't figure out where I saw the stats for minimum/maximum ranges on these guns.

[chuckdyke]

6 hours ago, mjkerner said:

I fired it up the scenario and was able to call for undirect fire within 165 yards of my FO in the church tower. (The guns were in the back of the map where they were initially, I unlimbered them in place.) However, things got interesting because the gun itself appeared to be using direct fire, and its shells were hitting a building right next to the church that was in the path of the shell's trajectory to the target. 

Also, I could have sworn there was a bit in the BN manual or on the GUI itself that showed a minimum/maximum range for these infantry guns, but couldn't find anything.  They do in fact have a minimum range, just like larger mortars, but damn if I can find it. Maybe in a later manual?

Sorry for butting in but if you have excel you can calculate it. On map I agree it is basically a direct fire weapon. it is not much different than the 75 mm of the Sherman. In RL tank guns were used for indirect fire like the HMG's. Doing all these tactics maybe for a future edition.

[Warts 'n' all]

1 hour ago, mjkerner said:

I exploded the scenarios from the campaign a long time ago, and forgot that the de-compiler numbers them starting with "0", so I was actually testing on Battle 8. Still can't figure out where I saw the stats for minimum/maximum ranges on these guns.

Yes, me too. I was thinking of "Not so fast, Fritz". The final mission where the Germans are defending. It is interesting to zoom in on one of these guns and look at their design. The gap between the gun shield and the barrel is very small, and must have limited the elevation to just a couple of inches.

[Warts 'n' all]

3 hours ago, Warts 'n' all said:

The gap between the gun shield and the barrel is very small, and must have limited the elevation to just a couple of inches.

Although from what I've just read it was meant to have a fairly wide range of elevation. So perhaps it's very low trajectory is down to it's short barrel. Either way it's a fiddly little bugger to fight with.

"Swear box, Noddle Head."

[Vacillator]

Are we talking about this gun?

https://en.wikipedia.org/wiki/7.5_cm_leichtes_Infanteriegeschütz_18

Elevation is given as -10° to 73° and max range as 3550m (which agrees with that in the game).  No minimum is quoted, perhaps unsurprising with -10° depression?  In a quick in-game test I found you can aim 1m in front of the gun, which does seems a little bit too 'depressed'.  Thankfully the crews seemed sensible enough not to fire,  or perhaps they were not feeling 'depressed enough' )

Anyway, I had a similar experience with two of these in BN 'Cats chasing dogs' and ended up with my sturdy crews pushing them into LOS/LOF for direct fire.  They survived but very risky...

Edited February 9, 2021 by Vacilllator

[Warts 'n' all]

That is certainly the one that I was thinking of. I first encountered it in game when playing the CW Module battle "Linking up and Breaking out". On moving a HQ unit close enough to give it orders during the Set-up Phase, I then watched in dismay as every round in the opening minute hit a tree.

[Erwin]

I looked at this situation some more and the situation is even stranger than first thought.  Am assuming I read the compass correctly, the Germans start on the East Edge.  The town to be attacked is at the SW of the map.

Note that one has two FO's - but one gets similar results regardless which FO is selected, or whether they are situated one the RHS or LHS of the German set-up zone.  

1)  As predicted, one can use an FO to order indirect fire at locations at longer range (towards the W edge of the map).

2)  It appears as if the indirect fire is calculated from the NE corner of the map rather than from the gun itself.  So, if one wants to plot indirect fire in the NW part of the map, the minimum range is over 800 meters.  If one wants to plot indirect fire to the SW area of the map, the minimum range is under 700 meters.  ie:  It's as if the on-map gun is calculated to be offmap somewhere to the NE of the map.

3)  However, one can move the "active" target icon down the left hand edge of the map and the towards the gun itself.  So, one can order indirect fire all the way down the left edge regardless of range (or intervening buildings that block the FO's LOS) and then towards the gun itself to 0 meters range.  However, one cannot target anything down the RHS of the map.  

All this can be seen and tested in the SETUP turn of Mission 7 from Die Letze Hoffnung campaign.  

 

[Erwin]

Maybe this is what happens in the game:  When one tries to use an on-map gun, the system calculates that the gun (In the above scenario at least) is actually located several hundred meters to the NE of the map.  That would explain why one can order indirect fire to the NW, the West, SW and close to the South edge of the map, but not closer to the NE as that would put the gun within the minimum indirect fire range.

Probably this hasn't been noticed before since there are so few scenarios that feature on-map guns.  (I can recall only one other time in 13 years of playing CM2 where one had a scenario with on-map guns.)

[chuckdyke]

19 hours ago, Erwin said:

Maybe this is what happens in the game:  When one tries to use an on-map gun, the system calculates that the gun (In the above scenario at least) is actually located several hundred meters to the NE of the map.  That would explain why one can order indirect fire to the NW, the West, SW and close to the South edge of the map, but not closer to the NE as that would put the gun within the minimum indirect fire range.

Probably this hasn't been noticed before since there are so few scenarios that feature on-map guns.  (I can recall only one other time in 13 years of playing CM2 where one had a scenario with on-map guns.)

I tested this out with a single story house blocking your LOS the minimum range is just over 500 mtrs. 

[Bulletpoint]

21 hours ago, Erwin said:

Probably this hasn't been noticed before since there are so few scenarios that feature on-map guns.  (I can recall only one other time in 13 years of playing CM2 where one had a scenario with on-map guns.)

I tried to include them in a scenario I'm building, but found they are too buggy. In addition to the bugs you're finding, they also fire way too slowly, and have extremely high accuracy. Whereas this gun was in reality the opposite: Fast firing but with low accuracy. The barrel is shorter than your average d...uck.

Same bug seems to affect all on-map artillery.

Edited February 11, 2021 by Bulletpoint

[Erwin]

In addition, the German 75mm Inf gun says it can deploy in 45 seconds.  In the game deployment took 5+ minutes. 

However, once it started firing the first 2 or 3 shots were way inaccurate.  The 4th was on target.  It fired at least 3 shots in 45 seconds - which isn't too slow.  Another odd thing is that even though the gun comes with its own truck there is relatively little ammo supplied -  only about 20 HE rounds and a couple smoke.

9 hours ago, Bulletpoint said:

Same bug seems to affect all on-map artillery.

Do you mean in all titles or just CMBN?

[Bulletpoint]

11 hours ago, Erwin said:

It fired at least 3 shots in 45 seconds - which isn't too slow.

That gives a ROF of 4/minute.

That's very slow compared to the real gun's rate of fire: 8-12 shots/minute according to the wiki.

And that included time for aiming. Max ROF would be even higher, according to this guy.

 

Edited February 12, 2021 by Bulletpoint

[Warts 'n' all]

I can't help think that ForgottenWeapons.com should be done under the Trades Description Act. Even with my marbles rolling around on the floor I haven't forgotten seeing footage of it in a documentary back in the early 1970s.

[Erwin]

3 hours ago, Bulletpoint said:

That's very slow compared to the real gun's rate of fire: 8-12 shots/minute according to the wiki.

And that included time for aiming. Max ROF would be even higher, according to this guy.

Ok, that makes sense.  I'll add to the weird/odd phenomena list. 

The other issue is that from what I could tell the CM system seems to calculate that when attempting to use the gun for indirect firing (at least during during the set-up turn), the on-map gun location is calculated to be several hundred meters offmap.  It's the only explanation that works for why one cannot plot indirect fire on certain parts of the map that are the same distance from the on-map gun as other parts of the map where one can plot indirect fire.

[Bulletpoint]

39 minutes ago, Erwin said:

he other issue is that from what I could tell the CM system seems to calculate that when attempting to use the gun for indirect firing (at least during during the set-up turn), the on-map gun location is calculated to be several hundred meters offmap.  It's the only explanation that works for why one cannot plot indirect fire on certain parts of the map that are the same distance from the on-map gun as other parts of the map where one can plot indirect fire.

I haven't noticed this issue, but I haven't been looking for it either. I know that when using off-map guns, their distance to target is calculated from the board edge (sometimes from the corner). So I could imagine that when using those guns on-map, somebody forgot to tell the game to use the gun's actual placement instead.