Military Ground Vehicles of Your Nation Mk X

[Chinevion]

What even is that gun depression

No more than 5 degrees for the ATGMS when aiming forward, about 7 degress for the cannon. 15 degrees aiming off to the side.

Raise it up a bit higher up,

[Fordorsia]

No more than 5 degrees for the ATGMS when aiming forward, about 7 degress for the cannon. 15 degrees aiming off to the side.

Raise it up a bit higher up,

Why? Don't have to.

[Chinevion]

Raise it up a bit higher up,

Why? Don't have to.

It is good just to have a bit more, it still is perfectly fine.

[The Akasha Colony]

Thanks for the help.
What kind of penetration would I expect from a 158mm tandem warhead atgm.

Either the same or worse than a 152 mm box-launched ATGM, as it may require thicker shell walls to protect itself during firing which may reduce the charge diameter below that of a box-launched missile.

True, but tandem warhead (think of a guided rpg 29 but guided) Pretty good at extreme ranges.

It would actually be kinda shit at extreme ranges, due to the extreme travel time and engagement cycle problems encountered by standard ATGMs. Your tank would probably be spotted and engaged by the target using LRPs before your missile reached the target.

Any tank launched ones?

No, and there are fairly big technical challenges. Namely that a missile launched from a gun has basically zero visibility before launch, given that it's stuck at the end of a long tube. Thus, its seeker cannot spot and lock on to a target before launch like almost every existing F&F ATGM. So you either have to hope it randomly locks the right target or you have to have a man in the loop to guide it, which is why existing gun-launched ATGMs like LAHAT and Svir/Refleks are laser-homing or beam-riding.

The other issue is that it's simply unnecessary at this point, gun-launched ATGMs are a less useful choice than guided tank rounds and can already be carried by plenty of other vehicles like IFVs or even dedicated ATGM carriers. This is why there has generally been no serious interest in developing gun-launched ATGMs in the West in the first place aside from LAHAT, which itself hasn't been much of a success.

[Fordorsia]

Why? Don't have to.

It is good just to have a bit more, it still is perfectly fine.

It's good if you're fine with a higher profile with no practical gain. Overall it's only 2.41m, which I'd like to keep.

[Chinevion]

Thanks for the help.
What kind of penetration would I expect from a 158mm tandem warhead atgm.

Either the same or worse than a 152 mm box-launched ATGM, as it may require thicker shell walls to protect itself during firing which may reduce the charge diameter below that of a box-launched missile.

True, but tandem warhead (think of a guided rpg 29 but guided) Pretty good at extreme ranges.

It would actually be kinda shit at extreme ranges, due to the extreme travel time and engagement cycle problems encountered by standard ATGMs. Your tank would probably be spotted and engaged by the target using LRPs before your missile reached the target.

Any tank launched ones?

No, and there are fairly big technical challenges. Namely that a missile launched from a gun has basically zero visibility before launch, given that it's stuck at the end of a long tube. Thus, its seeker cannot spot and lock on to a target before launch like almost every existing F&F ATGM. So you either have to hope it randomly locks the right target or you have to have a man in the loop to guide it, which is why existing gun-launched ATGMs like LAHAT and Svir/Refleks are laser-homing or beam-riding.

The other issue is that it's simply unnecessary at this point, gun-launched ATGMs are a less useful choice than guided tank rounds and can already be carried by plenty of other vehicles like IFVs or even dedicated ATGM carriers. This is why there has generally been no serious interest in developing gun-launched ATGMs in the West in the first place aside from LAHAT, which itself hasn't been much of a success.

Ahh got it, thanks for the help.

[Chinevion]

It is good just to have a bit more, it still is perfectly fine.

It's good if you're fine with a higher profile with no practical gain. Overall it's only 2.41m, which I'd like to keep.

What about telescoping, so you can raise it up a bit if nessecary

[Fordorsia]

It's good if you're fine with a higher profile with no practical gain. Overall it's only 2.41m, which I'd like to keep.

What about telescoping, so you can raise it up a bit if nessecary

Again, there's no reason for the added weight, size and complexity of a such a mechanism. It can already shoot at nearby infantry and down inclines.

[Chinevion]

What about telescoping, so you can raise it up a bit if nessecary

Again, there's no reason for the added weight, size and complexity of a such a mechanism. It can already shoot at nearby infantry and down inclines.

Ok.
Also my ignorance showing again, What's an LRP?

[The Akasha Colony]

Ok.
Also my ignorance showing again, What's an LRP?

Long rod penetrator. A term for the penetrator part of an APFSDS round.

[Chinevion]

Ok.
Also my ignorance showing again, What's an LRP?

Long rod penetrator. A term for the penetrator part of an APFSDS round.

Got it. I'm thinking of downsizing to a 150-152mm would this be more sensible?

[The Akasha Colony]

Got it. I'm thinking of downsizing to a 150-152mm would this be more sensible?

It wouldn't be substantially different.

[Chinevion]

Got it. I'm thinking of downsizing to a 150-152mm would this be more sensible?

It wouldn't be substantially different.

Lighter shell, marginally faster reload.
The guys in my rp group insist that I should downsize to a 140

[The Akasha Colony]

Lighter shell, marginally faster reload.
The guys in my rp group insist that I should downsize to a 140

Loading speed doesn't magically scale based on round size when an autoloader is used.

The expected tactical use of this weapon though is something I find rather pointless. Either all of your tanks should use this gun or none of them should. Which is to say, if you are facing threats that warrant such a large gun, then all of your tanks should need it, because they will all need to be able to deal with these threats. But if you are not facing threats that warrant this gun on every tank, there isn't much of a need for it on just one tank either, so you don't need it at all.

[Fordorsia]

vroom vroom, coming along nicely I think

Thoughts?

[Austrasien]

Lighter shell, marginally faster reload.
The guys in my rp group insist that I should downsize to a 140

Bore diameter is much less important than people tend to think. The amount of propellant used in the gun and its burning rate has a much bigger influence on the size and weight of the gun and ammunition than the diameter of the bore. If you had a 158mm gun designed to fire rounds with the same muzzle energy as the old conceptual NATO 140mm guns the weight of the gun tube and the weight of the ammunition would be very similar. At constant energy the main disadvantages of the bigger gun will be greater length, which reduces accuracy, and higher parasitic mass on APFSDS rounds from the larger sabots.

Shrinking the bore diameter to ~152mm would be fine though. Russia is working on a tank gun of this caliber and has built a number of prototypes in the past. This diameter is also the most popular caliber for anti-tank missiles so it is well suited for any guided rounds you might desire.

[Chinevion]

Lighter shell, marginally faster reload.
The guys in my rp group insist that I should downsize to a 140

Loading speed doesn't magically scale based on round size when an autoloader is used.

The expected tactical use of this weapon though is something I find rather pointless. Either all of your tanks should use this gun or none of them should. Which is to say, if you are facing threats that warrant such a large gun, then all of your tanks should need it, because they will all need to be able to deal with these threats. But if you are not facing threats that warrant this gun on every tank, there isn't much of a need for it on just one tank either, so you don't need it at all.

The country I'm expecting to use it against, is basically modern day germany, just with no post ww2 restrictions.

[Chinevion]

Lighter shell, marginally faster reload.
The guys in my rp group insist that I should downsize to a 140

Bore diameter is much less important than people tend to think. The amount of propellant used in the gun and its burning rate has a much bigger influence on the size and weight of the gun and ammunition than the diameter of the bore. If you had a 158mm gun designed to fire rounds with the same muzzle energy as the old conceptual NATO 140mm guns the weight of the gun tube and the weight of the ammunition would be very similar. At constant energy the main disadvantages of the bigger gun will be greater length, which reduces accuracy, and higher parasitic mass on APFSDS rounds from the larger sabots.

Shrinking the bore diameter to ~152mm would be fine though. Russia is working on a tank gun of this caliber and has built a number of prototypes in the past. This diameter is also the most popular caliber for anti-tank missiles so it is well suited for any guided rounds you might desire.

Thanks for your answer

[The Akasha Colony]

The country I'm expecting to use it against, is basically modern day germany, just with no post ww2 restrictions.

That doesn't tell me anything useful. What does it even mean? Germany without the effects of WWII and the Cold War? WWII and its after-effects have defined Europe for most of the last century. Who knows what Germany would look like without WWII?

What matters is what kinds of physical threats you're trying to deal with. What specific types of targets do you need to kill, and how much firepower do you need to kill them?

Contrary to popular belief, militaries aren't particularly interested in MAXIMUM FIREPOWER, they're most interested in the cheapest option to get the job done effectively. Unless there is a specific type of target that necessitates a 158 mm gun (like, say, a particular type of enemy tank), there's no reason to use it over a smaller caliber.

[Chinevion]

Should i use a Krasnopol type guided round

[Fordorsia]

How is a 158mm supposed to be better anyway? Just beef up your previous gun to use a larger propellant charge and maybe make the dart heavier. Simply increasing bore diameter means nothing.

[Chinevion]

The country I'm expecting to use it against, is basically modern day germany, just with no post ww2 restrictions.

That doesn't tell me anything useful. What does it even mean? Germany without the effects of WWII and the Cold War? WWII and its after-effects have defined Europe for most of the last century. Who knows what Germany would look like without WWII?

What matters is what kinds of physical threats you're trying to deal with. What specific types of targets do you need to kill, and how much firepower do you need to kill them?

Contrary to popular belief, militaries aren't particularly interested in MAXIMUM FIREPOWER, they're most interested in the cheapest option to get the job done effectively. Unless there is a specific type of target that necessitates a 158 mm gun (like, say, a particular type of enemy tank), there's no reason to use it over a smaller caliber.

Imagine modern Germany military wise, but larger, has more land, (think the German empire), none of the post ww2 no invasions. They use a tank similar to the Leo 2 but with more armor. They have the terretories of sirilanca and other areas that are historically mine. Due to political ideological differences and years of tension, a war is likely.
Their mbt has armor comparable to a t-14s armor. Our current tank is incapable of dealing with this threat, and our doctrine has mainly been fast strikes, which are not going to be possible. As you said, we are not interested in maximum firepower, usually using a 120 mm but now a new tank is nessesary. I have also decided to use a more sensible 152.

[Fordorsia]

more sensible 152.

What makes you think this?

[The Akasha Colony]

How is a 158mm supposed to be better anyway? Just beef up your previous gun to use a larger propellant charge and maybe make the dart heavier. Simply increasing bore diameter means nothing.

Wew lad. Let's lay off the edge there.

Bore diameter isn't irrelevant. It's a fairly important metric, just not in the way that most people expect. Increasing the bore diameter won't automatically increase gun power, but it does increase the practical limit of that power. A larger bore diameter can more easily handle larger propellant charges. After all, if bore diameter meant nothing, there would be no reason for NATO to have looked at 140 mm guns in the 1980s, Germany to be looking at 130 mm guns now, and the Russians to have been toying with 152 mm guns for the last few decades.

Realistically speaking, the current crop of 120 mm guns are reaching the limits of their performance. There is still room to eke out better results, but this is mostly limited to improvements in penetrator design and new propellant formulations with longer sustained burn time to maximize energy without exceeding the gun's peak pressure limits. And all of this is very expensive research for only modest gains. There is the option of developing a newer, even higher-pressure 120 mm gun since the current crop of 120 mm guns is of course descended from 1970s metallurgy, but this would still require the replacement of the old guns and the development of newer, higher-power ammunition which would likely also require modifications to the ammunition handling systems. Rheinmetall is supposedly pursuing this option anyway as a stopgap in the form of the 120 mm L/55A1, though.

Which means the easiest option to significantly increase penetration is to simply move to a larger bore diameter. Ceteris paribus, a 140 mm gun built with the same technology and using the same penetrator technology as a smaller gun will obviously provide far more muzzle energy and penetration than a 120 mm gun, and it provides more room to grow. The obvious downside is that it would require a new crop of tanks built around the gun or with the intent of upgrading to it, but as the Cold War tank fleets start aging, this is looking more enticing anyway.

So "increase the propellant charge" and "use a heavier dart" in an existing 120 mm gun is probably not a sufficient solution, although it depends on exactly what threats are being faced.

[Austrasien]

Should i use a Krasnopol type guided round

Do you need it? In Central European terrain most engagements can be expected to occur at ranges well under a kilometer. Guided projectiles are only really desirable at engagement ranges over 3 kilometers. This will only be common in desert and steppe environments. At ranges under 1.5km - still longer than what you can expect on average in that terrain - APFSDS have a flight time under one second, are virtually guaranteed to hit and will have nearly the same energy as at the muzzle.