Mercenary Artillery Ranges Fixed

[tbeard1999]

I moved this to a new thread from the Aslan thread.

EDIT -- ranges revised after consulting my notes.

I try to stay out of these hatchet fights because they do not involve me, but I really cannot keep silent on this anymore. This is the exact kind of post that gives this place the rep it has. And just so there is no mistake, this place as a rep of being completely and totally hostile to Mongoose Traveller, both the company that publishes it and those that like it.

While his tone was clearly hostile, the content of his criticisms are reasonable. Mercenary has outlandish ranges for artillery (p 105, second printing). In fact, they are *so* outrageous that I have to think that they are typos.

Anyhow, in the interest of amity, here are my opinions of the effective ranges of various weapons (TL9- data pulled from my research for A Fistful of TOWs):

Mortars

TL3 Field Mortar --no historical analogue found. At TL3, mortars were huge iron things. IIRC, there were smaller Coehoorn (sp?) "field mortars" used at TL3-4, but I haven't found any info on them.

TL8 Field Mortar. There are actually several classes of mortar that could fit this designation:

6 cm mortar -- maximum range ~3.5km; minimum 70m, mass ~20 kg, ammo 3 kg/round
8 cm mortar -- maximum range ~6.0km; minimum 100m, mass ~40 kg, ammo 7 kg/round
10 cm mortar (aka 4.2") -- maximum range ~7.5km minimum 120m, mass 150-300 kg, ammo 15 kg/round
12 cm mortar -- maximum range ~8.2km; minimum 200m, mass 325+ kg, ammo 20 kg/round

Only the 6cm mortar is portable by a single man (and even it would need someone else to carry the ammo).

TL 11 Field Mortar -- Generally, this system wouldn't be deployed in the OTU. By TL11, disposable 60mm multiple rocket launchers will replace infantry portable mortars. If such a system is deployed, a reasonable projection of technology would give it at most twice the range of TL8 systems. The conservative tech assumptions of Striker yield only a 20-25% range increase by the way.

AT Gun

Again, a wide variety of systems can fit this designation, from a 20mm TL5 AT rifle to a 125mm TL8 smoothboore gun.

However, line of sight engagement ranges are limited by the technology of the sighting systems (and eventually the curvature of the Earth or whatever planet we're on).

At TL5, the largest AT guns would have an effective range of about 1000m

At TL6, manual ballistic computers and early coincidence rangefinders would boost this to about 1500m.

At TL7, digital ballistic computers and stadiametric rangefinders would boost this to about 2500m. (2000m for less powerful weapons like the 105mm L51 rifled gun or the Russian 100-125mm smoothbores).

At TL8, advanced ballistic computers, wind sensors, barrel droop sensors and laser rangefinders would boost this to about 3000m. (2500m for medium powered guns like the L51 above).

I'd increase this by 500m per TL after TL8, and 1000m per TL after TL12.

Non-line of sight engagement ranges are better, but require smart projectiles (really only viable at TL8).

At TL8, effective range is about 8 km.

I'd add 2km per TL after TL 8. However, note that these projectiles are expensive and hard to manufacture. They also compete with tactical missiles. Finally, they require some way to spot the target (at TL8+, battlefield networks do the trick, although they may be susceptible to countermeasures). IMHO, non line of sight munitions will remain an auxilliary weapon system for main battle tanks for the foreseable future.

Note that for line of sight engagement, maximum realistic range to hit something would be about 50% more than effective range. So a TL9 AT gun might have an effective range of 3.5km, and a long range of 5.25 km.

Also note that line of sight engagements will be heavily restricted by terrain. In Western Europe, for instance, the Cold War Soviet Army expected to fight most battles at less than 2 km range.

"Frag Cannon"

I'm gonna assume that this is a fancy term for field artillery.

At TL5, light field artillery (105/122mm) will have a range of about 12 km. At TL7-8, it has a range of about 15 km, with rocket assisted projectiles reaching out to 21 km. At TL9+, range probably increases by about 2 km (3 km for rocket assist) per TL over 8.

At TL5, field artillery (155mm) will have a range of about 15 km. At TL7-8, it has a range of about 18 km, with rocket assisted projectiles reaching out to 30 km. At TL9+, range probably increases by about 3 km (5 km for rocket assist) per TL over 8.

MRL Pack

Again, a HUGE variety of weapon systems.

At TL5, Light MRL systems (100mm-199mm) have a maximum range of about 10km. By TL6, range is about 20 km. By TL 8, range is about 30km. At this point, propellant technology and countermeasures (rockets are easier to shoot down than artillery shells) cap out performance. I'd add +5 km per TL after 8.

At TL5, Medium MRL (200mm-299mm) systems have a maximum range of about 15km. By TL6, range is about 30 km. By TL 8, range is about 40km. At this point, propellant technology and countermeasures (rockets are easier to shoot down than artillery shells) cap out performance. I'd add +8 km per TL after 8.

At TL7, Heavy MRL (300mm) systems have a maximum range of about 70km. By TL 8, propellant technology and countermeasures (rockets are easier to shoot down than artillery shells) cap out performance. I'd add +10 km per TL after 8.

Mass Driver

Again, a large variety of systems. However, no plausible energy model can rationalize a 1000 km range. If such power were available, energy weapons would be far more effective than mass drivers. Mature (TL10-11) mass driver systems will probably produce double the range of chemically propelled rounds, with modest improvements thereafter. So use the AT gun or "Frag Gun" chart and double the ranges.

There...problem solved.

Caveat -- this is pulled from memory, so consider it a "first draft". The data should be free of any howlers.

 

[mbrinkhues]

Mortar ranges are a bit off for the big tubes respectively their TLs since mortars don't improve much after WWII/Korean War when it comes to range, they mainly got lighter. And mortars have no effective range, just a maximum one since they are artillery weapons

Also I would group the 10 and 12cm tubes into one group as they are employed and used in the same way. Actually the 107mm US tubes are an exception rather than an average. Maybe add a fourth group for the big ones (160 and 240mm mortars)

Another question is how to handle special ammo like target seekers (Availabel today) for mortar rounds 80mm and above.

=====================

As for the artillery range is less a factor of TL once you reach WWI but of barrel length/weight. WWII saw guns that could shoot it out with the best towed (or self propelled) howitzers of today but those where extremly heavy and given the lack of towing vehicles rarely used. So I would not make much allowance for TL past TL6 for the basic gun. The rest is some ammo design, not gun design (i.e TL8 Base Bleed rounds can be fired from a TL6 tube)

 

[tbeard1999]

Mortar ranges are a bit off...

Here are some Real World field mortars for comparison:

[b]Caliber	TL	Design.	Range	Mass[/b]
6cm	5	M2	1800	19
	6	M19	1800	20.5
	7	M224	3500	21.1
8cm	5	M1	3000	61.5
	5	GrW 34	2400	57-62
	6	M29	4500*	55.1
	7	M252	6000	41.27
10cm	5	M2 4.2"	4000	151
	6	M30	6800	305
12cm	6	GrW42	6050	280
	7	M120	7200	326
	8	Dragonf.	8200	mounted

The GrW models are WWII German; the rest are US.

Range is maximum range in meters; mass is kg.

From this, we can see that mortars have seen a dramatic increase in range from TL5 to TL8. However, there are a variety of reasons this won't continue. The biggest reason IMHO is propellants. While TL10-ish ETC rounds may provide as much as a 50% increase in range, they won't provide the kind of outlandish jumps shown in Mercenary. Better ballistic design and rocket assisted projectiles might extend range another 50% (at greater expense and weight [or reduced warhead] respectively).

I'd suggest that TL8 mortar ranges will increase 50% at TL 10 and double at TL11.

By TL10 munitions will be "brilliant" and will be indistinguishable from tactical guided missiles. Mass artillery barrages will be a thing of the past.

 

[saundby]

Ty,

Thanks for posting this. Very well done. Good figures I can use without any problems.

It'll be interesting to see what effects current developments have on weapons such as mortars. Work on the ability to intercept ordinance en route is advancing presently, as well as work on reducing the time to target to reduce the vulnerability of ordnance.

Near-future Earthbound ordinance is looking more like "Brilliant Pebbles" or "Sapient Sand" all the time as I look forward.

 

[mbrinkhues]

Here are some Real World field mortars for comparison:

[b]Caliber	TL	Design.	Range	Mass[/b]
6cm	5	M2	1800	19
	6	M19	1800	20.5
	7	M224	3500	21.1
8cm	5	M1	3000	61.5
	5	GrW 34	2400	57-62
	6	M29	4500*	55.1
	7	M252	6000	41.27
10cm	5	M2 4.2"	4000	151
	6	M30	6800	305
12cm	6	GrW42	6050	280
	7	M120	7200	326
	8	Dragonf.	8200	mounted

The GrW models are WWII German; the rest are US.

Range is maximum range in meters; mass is kg.

From this, we can see that mortars have seen a dramatic increase in range from TL5 to TL8. However, there are a variety of reasons this won't continue. The biggest reason IMHO is propellants. While TL10-ish ETC rounds may provide as much as a 50% increase in range, they won't provide the kind of outlandish jumps shown in Mercenary. Better ballistic design and rocket assisted projectiles might extend range another 50% (at greater expense and weight [or reduced warhead] respectively).

I'd suggest that TL8 mortar ranges will increase 50% at TL 10 and double at TL11.

By TL10 munitions will be "brilliant" and will be indistinguishable from tactical guided missiles. Mass artillery barrages will be a thing of the past.

Actually one of the major reasons for increased range between TL6 and TL8 is barrel length and propellant weight not technology.

ETC (Electrothermal-cemical) with mortars and artillery is questionable IMHO. It needs a shell casing that mortars and heavier artillery normally lacks (NATO 155mm fires bagged charges, mortars use external boosters. US programs (Crusader) concentrated on Liquid Propellant (LP) technologies to reduce the propellant weight.

ETC might work for some AT weapons but even here it's proplematic since cased 120mm rounds are problematic to handle due to size/weight (The 120mm Rheinmetall uses a combustible shell)

The future for artillery IMHO is in Electro-Magnetic (Gauss) technology, even more so if you start putting fusion engines in a tank.

===============================

One of the next developments IF they manage Anti-Artillery point defence will be a warhead that can "dodge" combined with more advanced cluster shells. Steerabel warheads already exist with calibers as low as 81mm

 

[tbeard1999]

Actually one of the major reasons for increased range between TL6 and TL8 is barrel length and propellant weight not technology.

Agreed, but wouldn't these be technological improvements (better metallurgy, somewhat more powerful propellants, etc.)?

However, designers can't indefinitely increase the length of a mortar barrel without compromising its usefulness:

1. Since the expansion of gasses increases over time, lengthening a barrel does increase projectile velocity (and range). However, there is a limit beyond which increasing barrel length provides no additional benefit.

2. Increasing barrel length makes the weapon heavier, so metallurgical tech has to improve. To a point, better design skill can allow for thinner barrels without improvements in metal, but I think that we've reached that point with TL8 CAD/CAM and modelling systems. After TL8, metal tech will have to improve dramatically. Also, excessive barrel length can compromise transportability in the case of infantry mortars.

3. Agreed generally re:ETC. I've been skeptical of it as well. However, it is a prostulated Traveller tech, so I felt that it should be included. And it will require serious improvements in metallurgy if it is going to increase velocity by ~50%. So my estimate is an aggressive one.

So at the end of the day, I think we're in agreement that while we may see evolutionary improvements in chemically propelled mortars, they won't be dramatic.

And while gauss weapons offer serious theoretical advantages (no effective limit on velocity; no explosive stress on barrel), they also come with formidable disadvantages (serious power requirements, delicate mechanisms, etc.). And while self propelled mortar carriers may carry gauss mortars, I don't see infantry portable gauss mortars unless fusion plants get very tiny and very cheap.

Regarding point defense -- IMHO, active point defense systems will render indirect weapons fire largely ineffective unless the active PD systems can be suppressed (or overwhelmed by sheer numbers). The problem with maneuverable systems (or systems with other countermeasures) is that such capabilities (a) dramatically increase the cost of the munitions; and (b) dramatically reduce the warhead size. Therefore, I expect direct fire systems to rule future battlefields, at least in conflicts between technologically equal opponents. Infantry portable AT weapons will be much faster (and therefore far shorter ranged, due to weight concerns). (I've been doing a lot of thinking about this as I contemplate the near future variant of A Fistful of TOWs 3.)

All this is a Good Thing IMHO because it brings tanks back into the forefront.

 

[tbeard1999]

Note--modified ranges on initial post above.

 

[mbrinkhues]

The main reason barrels where kept short and in case of a german WWII mortar actually shortened was portability. Only when someone started adding engines to a towed gun (i.e FH-70 155mm howitzer) did long-barreled towed guns become doabel. Same for mortars, the 120mm mortar used by the Bundeswehr (a 1950s design) is a good deal bigger than the one used in WWII. That's due to the fact that the WWII mortar was often towed by horse and even in trucks a 75HP engine was powerful in those days (not to mention the lack of 4WD). Today the beast is towed by a 4x4 Unimog with lots of power to spare so a heavier system works quite well.


But still, case 2) has benefits, using CAD/CAM etc should allow lighter guns by optimizing the material use and lightening parts to the minimum necessary(1) That's actually a tendency that can be seen IRL. The latest 155mm towed (i.e M777) are lighter than the older guns and the same might be used with mortars. Main reason it's not done today is that small mortars (60, 80) are multi-loads and the big ones (100+mm) are mostly self propelled these days(2)

Agreed on the problems of maneuverabel ammo. Costs will increase, payload will shrink or shell length will increase (It did from WWII to today) making self propelled systems (and their loading aids) more necessary. That and high Rate of Fire, computet Time on Target salvos like the PzH-2000 can fire today will be used making towed artillery mostly useless at high TL8 and above.

Artillery missiles will stay IMHO, actually going back to smaller systems like LARS with large numbers of missiles (IIRC 2x18) instead of the "big missile" systems like MLRS/MARS (2x8) or ATACMS (2x1). Since missiles have an engine already making them maneuver is easier and the large numbers will overwhelm point defence.

Mortars will stay because their short flight times will make intercept difficult, even more true for the smaller mortars. Pournelle's "Mercenary" novels have a number of ideas that should work nicely for Traveller

Edit: And we definitly need rules for MagLev guns. HUGE MagLev guns to be used by zee Zolomanie. With names like Bertha or Dora.


(1) And then strengthening again to the minimum necessary for use by soldiers

(2) Currently assembling the parts for a 1:35 M106 SPM using a mix of Tamiya and Academy kits

 

[saundby]

I've worked on maneuverable munitions down to .50 BMG*, and at times, depending on how the acquisition process is running, there's been considerable potential for making maneuverable munitions quite inexpensive. Once a certain level of integration is reached--which is within present technical bounds--there follows only the need for a commitment to a certain level of production.

Whoever goes first will be paying the high costs, but like IC manufacture, after that it gets cheap, if you produce enough.

If you stick with boutique style programs, though, you get to pay the startup costs all over again with each new program. Because of this having a "killer app" like a cave follower produced in limited numbers won't necessarily break the dam.

Hence the work on small bore--the thought being start small with high production rates, to build the base for making the tech ubiquitous.

[shrug] Nothing new so far as bringing new tech into the field goes. But a lot of the tech dev bills have at least already been paid at this point. In the present environment, I can't see it getting bought except in the small, expensive lots for select missions, if at that. Its certainly not in line with the direction current DoD thinking is going.

*A small IR&D tech demo, the actual program target was 20mm, but we wanted to show off, since we could.

 

[tbeard1999]

I've worked on maneuverable munitions down to .50 BMG*, and at times, depending on how the acquisition process is running, there's been considerable potential for making maneuverable munitions quite inexpensive. Once a certain level of integration is reached--which is within present technical bounds--there follows only the need for a commitment to a certain level of production.

What's the Real World effect of smart small arms munitions? Are they more accurate? Or are they able to do neat things with fusing and the like (such as the 20mm fragmentation round that can fly over the heads of dug-in troops and detonate)?

 

[saundby]

The two applications I worked on were terminal guidance and indirect fire. We saw other uses, like fused munitions, coupled with these, but weren't working on them, aside from an inert mockup I did of a shell with a penetrator-firing warhead. It wouldn't have been compatible with present systems so it was just used as window dressing, but available if anyone felt like giving us the money to develop it. .

Indirect fire was tricky--telling the rounds what to do was the problem--but we demonstrated active guidance of fire onto a non-line-of-sight target. We weren't up to 5th Element standards by a long shot.

We had two modes of terminal guidance: light guided (this is what we did in .50BMG) and motion sensitive.

For the technology we were using, the smaller, lighter rounds were easier for us. We dreaded having someone ask us to do it in a 6 or 8 inch shell until we'd had a chance to go into production with what we knew we could do.

This was all some time ago for me. I don't know how much farther they've gone (if at all) since I worked on this. I know there was active work on the communications when I moved on.

The tech used was a lot simpler than gets used for comparable applications in, say, missiles. The big deal was integration. Once we'd learned how to integrate electronics into tank shells, we started seeing what other applications we could create with that knowledge (our normal line was in systems with far lower g-forces.)

 

[Jame]

I wrote up my own version of it, but thoroughly unresearched. So ...

WHAT? HOW DARE YOU BEAT ME TO IT!?! :devil:

Now that the insane competitiveness is dealt with, I'm glad someone got to it with research. I may, someday, borrow this.