So I've been busy working on a mercenary campaign I hope to run for some friends over the next few weeks. Of coarse one of the main perks of a merc campaign is that the PCs actually get to play with some of the really big guns presented in the SR4 rules.

But reading through some of the descriptions I've noticed some very loose definitions of the word "cannon" in the SR canon. This has always annoyed me a little. In various SR publications you have assault cannon, autocannon and of coarse the GM light and heavy cannon presented in Arsenal, all of which seem to be different from one another as well as different from one edition to the next.

Assault cannon, for example, used to fire exploding shells, but don't appear to do so any longer, based on their SR4 rules and descriptions. Now-a-days they sound more like anti-tank or anti-material rifles, or maybe recoilless rifles. And "autocannon" really sound more like large miniguns or maybe chain guns.

But I digress. What I'm really interested in is getting some opinions on the following:

1.) What is your definition of assault cannon and/or autocannon?

2.) Can the GM cannon presented in Arsenal be used for indirect fire, or are these intended as exclusively direct fire weapons (as the term cannon technically implies)? I want to adapt the GM cannon to use as howitzers. I was thinking I'd use them basically as presented, but allow them to use indirect fire, and shells that use the rules for different mortar rounds.

3.) Along the same lines, modern cannon such as the Rheinmetall 120-millimeter main gun mounted on an M1A1 fire a variety of rounds. How would you adapt the rules for different mortar rounds to use as ammo for a direct fire cannon? How would you alter them? Smaller blast radii seem prudent, but I'm curious what others think.

As always, any ideas are greatly appreciated!!

we treat the assault cannon like a 20mm AA cannon from ww2. if you remember the final battle in Saving Private Ryan the germans use one mounted on wheels. When the Para's swarm over the 1st Tiger tank after Tom Hanks knocks it out, the germans open fire with it and it proceeds to just blow them to chunky salsa. Big slugs with lots of kenetic power,called a 'cannon' just because of it's size, not because of explosing shells.

Ah yes the Flak 30. Great scene. This is how you image the SR assault cannon? I assume you mean as a single shot 20 mm rifle. Like this wonderful weapon? or this? Anti-tank rifles really.

the thing about future trends is we're moving more and more towards guided and precision weapons. not necessarily "smart" weapons, but cannons, mortars, and artillery pieces that can either A: fire guided shells, or B: accurately predict where their "dumb" shells will land. gone will be the mortar that will be set up by a crew of men, then manually oriented and aimed. instead we'll have things like the AMOS, which is more of a hybrid of mortar, cannon, and howitzer. these will be mounted on AFVs, and complimented by things like the NETFIRE missile system, (which was recently canceled, due to Artillery guys not wanting to be out of a job).

in a nutshell, Direct fire and indirect fire weapons will be one and the same, as you really can't afford to not have that flexibility on the battlefield.

1) I would say the SR assault cannon is the love child of a high-velocity grenade launcher and a low velocity autocannon. The contemporary Barrett XM109 payload rifle matches my mental image perfectly.

2/3) Since SR is largely a urban, CQB-focused game, I would use mortar stats for just about everything. They are big enough to scare the players, and you already have the stats.

If you take your mercs out of the sprawl, where you _don't_ have a concrete wall or vehicle every 50 feet, then the distinction between a 10lb mortar shell and a 40lb artillery shell might become important.

Where re you getting this whole "assault cannons don't fire explosive rounds" thing from, exactly?

Assault Cannon Rounds: These highly stable explosive
rounds are made of HDX superplast compound.

That's from p312, BBB.

If you're not happy with the stats, fair enough, but the description is clear about them firing explosive shells.

Aside from the fluff, I can easily see how Method gets the idea.

All other explosives show a base damage plus how quickly the damage decreases. Assault cannon ammo doesn't. _Rule-wise_, it functions just like a non-explosive round.

You can be hugging a person while they get their head blown off by a panther cannon, and not take any physical damage.

I think they should be statted like grenade launcher shells, but a little less powerful.

The good doctor EDd_209a hit the nail on the head. Despite that line of fluff text under the assault cannon ammo, they give no rules regarding blast radius or effects.

EDIT to give give proper credit...

Neither does explosive ammo.

I don't really see the explosive ammo as "explosive" in the same sense as a grenade. More along the lines of a pre-fragmented core, with a very thin layer of explosive between each of the fragments, coated with a light metal jacket. The EX version would just give the design better AP characteristics and a little more "powder charge".

Micro-explosives for enhanced fragmentation is different than area effect explosive or rounds that deploy sub-munitions or any number of other specialized rounds available for modern cannon. True to SR's rampant firearm silliness, apparently you can get specialized ammo for a light pistols that are ridiculous (AV light pistol ammo? Seriously?) but you can't get explosive cannon rounds which have been around for hundreds of years!

I'm sure this will be rectified in the forth-coming military source book... <hint, hint>

want launched area explosives? grab a grenade launcher with a range finder, rocket/missile launcher or a mortar.

oh, and looking at the numbers, the av mortar round packs a punch somewhere between the light and heavy vehicle cannon.

so just bolt that to a turret and be happy. maybe up the range a bit for howitzer class...

btw, who brings a howitzer anywhere near the front line anyways? just have the team radio in the artillery requests, and let it rain mortar shells from afar

Or bolt it onto the side of a remote rigger controlled Skytrain... DIY Spooky gunship!

The Shadowrun assault cannon was based on the Cobra Assault Cannon from Robocop. It's based in turn off the Barrett M82A1 .50 cal, which I believe is classified as an AMR. In the movie, the Cobra fired explosive rounds, so the Panther did the same thing.

Ya got to mount miniguns and auto-grenade launchers to it as well for it to be a Specture gunship. (aka Puff the Magic Dragon)

Oh I got all that. I've already crunched the numbers for the modified Skytruck. Its really more of a combination of an Osprey, an AC-130 and an AWAC. The 20mm minigun and 40mm Bofors are easy (Vanquisher Autocannon and GM Light Cannon respectively). My issue is there is nothing that fits for the 105mm Howitzer, thus this here thread.

The devs have often said that they deliberately kept the focus away from military hardware, with the intention of covering this stuff in depth (along with extra material for mercenary campaigns) in a Fields of Fire style miltech book.

Until such time as this arrives, I see nothing wrong with your suggestion of just tweaking the ranges on Mortars. In fact it's barely even worth bothering with the tweak. If the players are firing from further than 6,000 metres, you probably need to get too caught up in the particulars of the combat rules. Just have 'em make some kind of Gunnery roll to put their suppressing fire in the right general area.

And I'm only slightly drooling over the thought of playing a Shadowrun game where you could actually call in Spectre gunship support. Those things are freaking awesome.

You could just go with the grenade launcher stats for an HE assault cannon round. However, a thing to note is exactly how the explosive explodes. Heat rounds and its sister the EFP (explasive formed penetrator (see http://en.wikipedia.org/wiki/Explosively_formed_penetrator) use a charge to create a penetrating blast rather than shoveling shrapnel all over the place. Then you have HE rounds, IPCM, cluster bombs (which could be HE, antivehicle or dual purpose). You also have HESH rounds wich are neat in that they are designded not to penetrate but cause the armor in a vehiche to break apart inside and kill the crew. APDS, (APDSFSDU, armor peircing discarding sabot fin stabilized depleted uranium, is an example) involve a hard penetratting dart that uses

GPS guided munitions may or may not be that common. The reason I say this is that guidance could be better calculated (computer calculates the range to targe, the right ange, and powder charge to use) from the shooting end and the need for the shelld to be precision based would be lessened.

Note there is a 500lb dumb bomb in Arsenel (pg 125). You could adjust that to suit your tastes.

I'd just got with bombs or rockets/missiles to replace the 105. much more flexible.

Gah where to start...

Generally, to qualify for the name of 'cannon' the weapon has to be useing a 20+mm projectile.

So 'miniguns' don't qualify as cannon, since they are rotary cannon scaled down to fire MG sized rounds.

A 'chain' gun refers to what mechanism is used to feed the next round, not the size of the round.

Recoilless rifles aren't referred to as cannons, that's why they are called recoilless rifles .

Note also that the line between a light cannon and automatic grenade launcher is somewhat hazy. The ASP-30mm is technically and autocannon, but very similar in size can capability to the Mk19 40mm automatic grenade launcher.

----------

Artillery fire. Really the size of the artillery (and round type) will make a very large difference in what the rounds do.

60mm mortar rounds can probably be simply modeled as hand grenades.
81mm mortar rounds have maybe half again as much oomph.
120mm mortar rounds will weigh in at around 12 kg (+/- 3 kg) and have around 2kg of explosive filler.

155 artillery rounds will weight in at around 45 kg and have around 10 kg of explosive filler.

Speaking in general, mortar rounds tend to have a higher percentage of weight dedicated to explosive filler because they operate at lower pressures than artillery cannon. So the shell structure doesn't have to be as tough, which means more space of explosives. Of course, there are several low velocity cannons specifically designed to get around this problem, but you don't kill armored vehicles with a low velocity gun...

---------

As for the effects of direct fire cannon rounds as compared to artillery, it is also sorta complicated.
For example, I don't think the US issues 120mm HE to its tank crews, and anti-personnel fire using the main gun will be with HEAT rounds. While the IDF does seem to have and issue 120mm HE.

Depending on stuff, I'd guess that a HEAT round is between 50% and 85% as effective as a plain HE round when it comes to killing exposed personnel.

heh, to much detaill for the SR system there...

im tempted to say that a keen interest in weapons and SR simply dont mix...

but then i guess that can be generalized to any keen interest and SR...

Assult cannon is just a name, the weopons in that class are actually anti material rifles firing explosive ammunition. Contrary to your first post where you said that they don't fire explosive round any more in SR4. So they don't have a blast radius, did you ever think that the explosive in the ammo are for causing more damage to the target and not for doing AOE damage.

The 120mm Mortar rounds we used in the military weighed 14,4 kg and had 3,3 kg of explosive in them.

I think the mantech M-12 mortar system in Arsenal is a 60mm (it doesn't say it but in comparison with grenade damage it would seem to match). You could probably scale it up from there for the larger calibers. Note the 120mm is typically towed or self propelled. The 81 mm is either mounted on a vehicle or maned by a weapon crew.

Stats for a Howitzer? Heh.

Roll to see what you actually hit.

It's gone.

Don't need many more stats than that.

The XM109 is derived from the M82, right? Looking on Wikipedia the photo of the Barrett M82 looked remarkably like the immage of the Ares Vigorous Assoult Cannon (Arsenal p.31)........ you could be right.

You can't effectively use an EFP in a cannon round. IIRC, it requires too much explosive to be effective.

However both a HEAT and an EFP have very deadly blast effect and certainly will produce fragmentation. Some rounds are designed to produce very deadly fragmentation. For example:

120-MM HEAT-MP-T CARTRIDGE M325 (CL 3105)

The M325 is a high-explosive anti-tank (HEAT) cartridge. This cartridge is a dual-purpose munition, which defeats medium-and light armored vehicles and Incapacitates infantry by blast and fragmentation.

I think you are overrating the grenades and under weighing the projectiles

An m67 grenade has about 0.18 kg of HE
A 60mm mortar round has about 0.36kg
An 81mm mortar round has 0.9kg
a 120mm mortar round has 3 kg
a 105mm howitzer round has about 2 kg
a 155mm howitzer round has 7kg

A projectile has lot more mass to convert to fragmentation than a grenade. Which is why an unprotected person standing within 50 meters of a 155mm round burst has a nominal 50% chance of needing a body bag, if they are lucky they just get the opportunity to test a surgeon's skill.

The M107 155mm round only has ~7kg of explosive filler, but is a very old design (~50 years), the newer M795 packs in around 10.8 kg of explosives, with a total weight of around 46-47 kg.

What about submunitions? Fragmentation is all nice and dandy, but I think we'd be seeing more artillery ordnance using submunitions than older designs in SR.

there were actually stats for a howitzer in one of those nifty little files on the old official shadowrun 3rd page . . i think it was the rigger toybox or something like that . .
there were stats for rubber-boats, RC Toys and electrical wheel-chairs and other such things too O.o

I'd say that you're absolutely right about this, but in fairness to the designers, I think that's because they have an absolutely monumental task facing them.

Shadowrun is, quite simply, one of the most nightmarish scenarios for a system designer to tackle. It's close enough to the modern day that people expect some kind of realism in everything; they expect guns to work the way they do now, they expect computers to work the same, they expect cars to work the same. If it was pure sci-fi you could just say "It's a disruptor" or "It's a hover car" and nobody would care. Shadowrun has to have those elements of realism, whilst still accomodating lasers, rail guns, pain inducers, full simsense computer systems, LAVs, semi-intelligent drones, etc.

Then you throw in the fact that it also has to not just be a fully worked out fantasy setting, but even there it has to be "realistic". You can't just say "these races exist, these magics exist, that is all", because part of the rationale for the setting means that they have to accomodate every magic system ever devised in human history, and every mythical creature we have ever imagined. Stop and think about how riduculous a task that is.

Now because it's a cyberpunk setting they can't just let hacking and computers be a minor part. They have to integrate it in such a way that hackers are main character worthy collossal bad-asses of the cybernetic world, or the Gibson and Stephenson fans will cry.

Vehicles will inevitably get a lot of use, so you have to have solid vehicle combat mechanics.

Again, it's cyberpunk, so you have to include cybernetics, but you have to include them in such a way that they interact with magic properly, without conflicting, or giving endless opportunities for overpowered character builds.

People are going to want to modify their gear in all sorts of interesting ways, and it's close enough to what people actually understand that you can't just handwave it away and say "no you can't." So all of your rules have to allow for the fact that gear is customisable.

Oh, in order to feel realistic the lethality has to be pretty high, so you need to be sure that your social mechanics are well written because they'll get a lot of use.

You have to take the entire planet Earth, in all of it's endless complexity, and somehow bring into a future that is only 60 years away, but with all the changes of the awakening, might as well be a 1000. You have to make everything accurately reflect it's modern state, whilst still changing things in interesting ways to reflect the changes that have happened, and to create interesting environments for the players.

And now, to top it off, you have to somehow integrate the three worlds of magic, mundane, and cyberspace into one system, in such a way that they don't conflict during play, and in such a way that they can actually interact in interesting ways, without making certain archetypes overpowered or redundant.

Now you guys could point out ways that the designers failed in every one of these, which is fair. My point is that they did pretty damn well to provide a system that handles all of these tasks as well as it does. Poke at anything in Shadowrun too hard and it's gone give way, because the game was never built around specialised interests. It can't be, and still cater to so many interests.

and this is something to keep in mind at all times.

If memory serves one of the old Third Edition State of the Art sourcebooks, the one that dealt with mercenaries not surprisingly, gave us details for a light howitzer that clocked in at about the same caliber as the current day M119 howitzer. Basically all they did was up the size and weight of the thing, make it use another skill to fire it, and increase the range of them compared to mortars plus give them special shells that did more damage - some of them even went into naval damage levels IIRC. If you can dig it out it shouldn't be that hard to convert over to Fourth Edition, or you could just make the details up yourself.

The whole concept of a slightly smaller AC-130 isn't that far into the realms of fantasy, the Air Force is apparently looking at eventually replacing the AC-130s with 'gunship lite' based on the AC-27J.

that would be state of the art 2063, it got a whole chapter dedicated to mercenary activity...

and as the main person from that chapter is still around in SR4 time, one may suspect a military grade hardware book at some point in the future...

here we have it.
but it's in german <.<
http://www.eisparadies.org/fileadmin/shado...ybox-online.pdf

Bah! Unless it's got a long fuse, fires a solid hunk of iron, and can only be fired by people wearing eyepatches who say "arrr" then it's not a real cannon!

You know, in a similarly old-school vein, I'm increasingly tempted to create a shadowrun rigger who builds all of their gear out of scrap. They'd have this huge workshop / junkyard where they build scrap cannons and salvage old motorcars. There'd be one room that's sealed off, with huge "Do Not Enter!" signs, where they're trying to build a mecha.

It's all tied to this "Trashpunk" subculture that I've been kicking around; it's mostly Orks and Trolls, smart guys who've had a pretty shitty education (because they come from crappy areas of town), but who've used matrix resources to teach themselves the stuff that they actually find interesting (like a lot of self-taught programmers today). We're talking guys and girls with natural smarts, but who don't focus their intelligence on academic achievement. Instead they embrace this ethos of making something from nothing, of taking all the crap that the world rejects (just like them, neh?) and building something amazing out of it. Music is heavily experimental, and heavily influenced by stuff like Stomp and the whole metal percussion idea. Think the music in that stupid-ass dance scene in Matrix Revolutions and you'd be on target. A lot of them get up to stuff like drag-racing their homebuilt cars, or building scrap mechs which they use to pit fight out in the barrens (heavy dose of Robot Wars in here). They dress in rejected clothing (a lot like the indie / grunge look of Salvation Army clothing), and even stitch together their own stuff out of scraps. Nothing has to look nice, it just has to be cool and functional; they're consciously rejecting societal ideals of beauty, because they don't feel that they will ever fit into those ideals. Instead they're proving that it's not looks but function that matters; that without any resources, without money or influence or whatever else, they can still achieve incredible things.