Recent discussions about the virtues of energy weapons versus ammunition-based weapons (again) sparked a rules discussion between my brother and I (his forum name is beyond.wudge) about how ammunition explosions could be rebalanced while staying true to BattleTech lore and the existing rules. We had tried out house rules for an ammunition explosion table in a few games and found that it made a large difference to the survivability of ammunition-based Mech designs and their appeal in Mech vs Mech combat. However, before I go into the rules in any detail, I think that it’s very useful to nail down the issues very specifically.
What is actually wrong?
Energy weapons are exceedingly consistent when compared to ammunition-based weapons as they cannot suffer catastrophic explosions that consume the Mech utterly. You can overheat and while in a land of single heat sinks that can be a very big deal, overall the consistency of lightbulb Mechs can typically outweigh the benefits of ammunition-based weapons in Mech vs Mech games (it has already been extensively discussed in other threads how the addition of other units types can radically change this equation and I take that as a given). In short, overheating is inconvenient whereas ammunition explosions are lethal. Issues surrounding certain weapons (such as the weight of autocannons) only compound this underlying issue.
What are these rules trying to achieve?
These rules try to reduce the number of catastrophic (ie normal) ammunition explosions and make ammunitions explosions more fun overall.
How are these rules trying to achieve this objective?
The current rules operate as follows: A critical hit is achieved, this hit is randomly applied against an ammunition slot, all of the remaining ammunition in that slot explodes, your opponent smiles and you damn yourself for not playing Clans. These rules only expand and modify what happens when the critical hit is randomly applied against the ammunition slot. Rather than a critical hit always causing a massive explosion (if sans CASE), there are many types of damaging results that fill out the space between nothing happening, and everything (bad) happening to your Mech.
The rules do not change CASE, CASE II or the basic method for resolving ammunition explosions. They simply affect the severity and frequency of these explosions once a critical hit has been inflicted. Additionally, wherever possible, existing rules have been employed and then expanded upon rather than creating new rules at every point. This is to make it easier for players to simply pick these rules up and plug them into their games (as opposed to reinventing the wheel).
Why is this change a good thing?
There are two reasons why you may wish to use these house rules in your game. The first is simply game balance; you may wish to buff ammunition-based units so that they are a more attractive choice versus energy weapon Mechs in a competitive context. The second reason is simply flavour. While ammunition explosions are reduced, there are also a few truly catastrophic results that can make life even more interesting. You may be a bit bored with the usual rules and want to try something a bit different. Also, these rules make catastrophic ammunition explosions rarer, so they may actually become more fun (more or less; think of headcapping and the like for an analogy).
How does this mesh with the existing fluff?
These rules strive to change as little as possible from a fluff perspective and ultimately, it could be argued that nothing has to change at all. Instead, these rules can be seen as fleshing out things that simply haven’t been covered in the rules before and as such they don’t change things; they merely add to them.
There are three crucial fluff ideas that these rules rely upon. First, it presumes that there is some sort of inherent system (or systems) that tries to prevent catastrophic ammunition explosions, whether through superior industrial design, sophisticated (but flawed) blow-out panels, internal armour or whatever else. These systems are different to CASE in that CASE is a very specific system that is exceptionally reliable (Era Report 2750 has an excellent description of what CASE actually is and how it is more than blow-out panels, etc). These systems don’t reach the CASE level of reliability or sophistication and that is why they have the random element. The rules below represent how these systems may help with an ammo explosion, but won’t always prevent it.
These rules don’t replace CASE; they fill the gap between absolutely nothing and CASE. They are designed to combine with CASE and CASE II seamlessly. What CASE gets you is certainty that your Mech won’t asplode due to ammunition going off; these rules simply give you a chance to survive. These rules affect what happens when an ammunition slot suffers a critical hit; they don’t change what CASE does to mitigate ammunition explosions.
Secondly, these rules also conceive of an ammunition slot containing more than simply the ammo itself. For example, the slot would also include the ammunition feed system that runs from that slot to all of the weapons that draw from it (expands on the notion of damaging the ammunition feed system in an individual weapon found on p76 TO, and applies it to the ammunition slot instead). Furthermore, the slot would include any number of ancillary systems, armour and other components that may mitigate damage sustained in that area and may “get in the way” enough to stop the ammo itself from being hit and ignited. As such, it would be possible to damage the slot and not necessarily cause the ammo to explode, just like the advanced rules for critical damage in TO represent that a weapon could take a critical hit and still possibly function, albeit in a reduced manner. However, such damage would probably make a catastrophic explosion more likely.
Thirdly, these rules presume that certain types of ammunition are more (or less) volatile than the norm and this is reflected in modifiers that apply to the chance of a catastrophic explosion. For example, infernos are very unstable, while MG ammo is less so (ok, ok; this is a little arbitrary and we’re fully aware that real-world MG ammo can explode pretty badly and catastrophically. As this is BattleTech and not the real world, we shall now use a healthy dose of Handwavium and presume that machine gun ammo is made of various types of mundane Unobtainium that makes it less explosive than standard Autocannon ammo. Having now used the Power of Arbitrary for the Sake of Rules Balance, can we move on? :).
These rules are designed to be as compatible with the fluff as possible and fit into the continuity of BattleTech rather than overwriting things; they are trying to add rather than replace. As such, these rules acknowledge CASE and that catastrophic ammunition explosions still happen but that there can be more to it than just that. These rules try to find a middle ground between the all or nothing of the current rules. On a side note, we understand why ammunitions function as they do in the game and in the universe; they’re fun. They can cause the momentum of the game to swing back and forth and they follow the “rule of cool”. These rules are an attempt to balance this out a bit more so that the swings aren’t so hard.
Do these rules apply to units other than Mechs?
No, simply because Mechs as the designated “kings of the battlefield” would have the best technology to preserve them, and the limitation of other designs (such as conventional vehicles) would probably prevent the use of such systems (although that doesn’t really explain why simply blow out panels wouldn’t work for vehicles, but then if vehicles survived ammo explosions and Mechs didn’t.......).
Nothing to see here; move along ;)
These rules are meant to be somewhat tongue in cheek and not overly serious. For example, we considered calling the rules the Ammunition Salvation System, but the unfortunate acronym caused us to go for a more innocuous title. Also, some of these results could easily be compressed and streamlined if being translated into a more “serious” version; we have a larger number of results simply to increase the flavour of the table.
And now, the rules:
Expanded Ammunition Explosion Rules
Whenever a slot of ammunition suffers a critical hit, the owning player must roll 2D6 on the Expanded Ammunition Explosion Table and apply all relevant modifiers to determine the result. Any modified results on this table that are greater than 14 count as 14 and less than 2 count as 2. While an individual ammunition slot can be hit multiple times under these rules and as such individual results on this table can be repeated for that slot, all modifiers are cumulative and eventually damage modifiers will ensure that an ammunition explosion of some description becomes inevitable. CASE and CASE II operate normally to limit the damage inflicted by ammunition explosions.
This table does not affect any ammunition explosions that result from a ‘Mech’s heat level. Ammunition explosions for One Shot and Hot loaded weapons are also resolved normally.
Ammunition Modifiers
+1 if ammunition slot contains non-inferno missile ammunition (type M weapons)
+2 if ammunition slot contains inferno ammunition of any kind (does not stack with modifier for missile ammo)
-1 if ammunition slot contains machine gun or AMS ammunition of any kind (standard, light, heavy, etc)
Era & Faction Modifiers (Optional)
+1 if faction is Periphery or Pirate
+1 if time of play is during the Succession Wars
-1 if tech base is Clan (yes, cheating Clans...)
Insert your own (quirks for ‘Mechs, etc)
Expanded Ammunition Explosion Table
2D6 Roll - Roll Effects
2 - Nothing Happens
You got lucky (unless you’re carrying infernos of course and in that case you deserve everything you get). The ammunition does not explode and as such the ‘Mech does not suffer any internal damage or hit to its MechWarrior. All further rolls on this table made due to subsequent critical hits to the affected slot will suffer an additional +1 modifier.
3 - No Going Back Now
Miraculously, the critical damage does not ignite the ammunition in the bay, but the mangling of the ammunition control subsystems means that the bay is more or less sealed until a technical team can prize them open after the battle. The ammunition does not explode and as such the ‘Mech does not suffer any internal damage or hit to its MechWarrior. However, the ammunition cannot be dumped and the bay can only be depleted through firing the appropriate weapons (hopefully with reckless abandon!). All further rolls on this table made due to subsequent critical hits to the affected slot will suffer an additional +1 modifier.
4-5 - Ammunition Feed System Damaged
While the ammunition doesn’t explode (this time), the feed systems are damaged beyond immediate repair and renders the ammunition useless for the rest of the game. The ammunition does not explode and as such the ‘Mech does not suffer any internal damage or hit to its MechWarrior. However, no ammunition in the affected slot may be used to fire any of the ‘Mech’s weapons for the rest of the game and the ammunition in that slot cannot be dumped during the game. Furthermore, any further rolls on this table made due to subsequent critical hits to the affected slot will suffer an additional +2 modifier.
6 - Explosion Suppressed
The damage control systems perform above and beyond the call of duty. The explosion is completely vented by releasing handy anti-explosion airbags to suppress the chain reaction (ok, I'm kidding here, its special foam ^_^). Resolve the ammunition explosion as if the ‘Mech were equipped with CASE II. However, instead of suffering only 1 point of damage as per the CASE II rules, the ‘Mech suffers 1+D6 points of damage.
7 - Blowout
Through superior design, excellent construction or sheer dumb luck, the damage control systems successfully trigger and vent the explosion out of the ‘Mech via a series of incredibly convenient blowout panels. Resolve the ammunition explosion as if the ‘Mech were equipped with CASE.
8 - Barely Contained Explosion (or “She Canna Hold It Captain!”)
The ‘Mech survives the ammunition explosion, but only just. Resolve the ammunition explosion as if the ‘Mech were equipped with CASE. However, the ‘Mech, suffers an additional 2D6 points of damage to its internal structure in the next location where damage would usually transfer (ie if the ammunition explosion occurred in the right torso, this damage would be applied to the centre torso). This damage may cause one or more critical hits as per the usual rules and may trigger additional ammunition explosions and the like.
9-12 - Catastrophic Failure
The ammunition explodes and there is nothing else to be done except to eject and hope for the best. Resolve the ammunition explosion normally and seriously consider about either installing CASE for next time, or playing Clans.
13 - Burninating The Countryside
Not only does the ammunition explode and completely consume the Mech, the ammunition takes a page from Trogdor and gives the surrounding countryside and any hapless units a good burnination. If the location of the ammunition slot is protected by CASE or CASE II, the ammunition explosion is resolved according to those rules. However, if there is no such protection, the ammunition explosion follows the rules given on p78 of Tactical Operations. As stated there, determine the total amount of damage caused by the detonation (generally equal to the amount of shots remaining times the maximum damage of each shot). Divide this amount by 10 (round down) and apply it as an area-effect attack in the destroyed unit’s hex, with all units in adjacent hexes taking half this damage (round down). As per those rules, CASE and CASE II in the relevant location will operate normally.
14 – The Stackpole Effect
A small mushroom cloud marks the last location of the unfortunate Mech and its probably cursed pilot. The ‘Mech suffers a critical (and technically impossible) engine-related explosion that would ensure the ‘Mech’s classification as a small weapon of mass destruction. The ammunition explosion is resolved normally. Additionally, irrespective of the existence of CASE, CASE II or any other cheating Clantech, the Mech explodes. The explosion follows the rules given for Engine Explosions on p77-78 of Tactical Operations. As stated there, the explosion destroys the Mech and all other units in the same hex, and also starts a fire in the hex, regardless of the terrain. Any units in adjacent hexes take damage equal to the engine’s rating divided by 10 (rounded to the nearest whole number; round .5 down). Units 2 hexes away take damage equal to the engine’s rating divided by 20. Units 3 hexes away take damage equal to the engine’s rating divided by 40. Divide this damage into 5-point Damage Value groupings and randomly determine each location; determine the direction of the attack from the direction of the hex where the engine exploded.