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Vampire
Free Worlds League
Lieutenant Colonel
Joined: 05-Feb-2002 00:00
Posts: 917
Location: Spain
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 Posted: 25-Nov-2011 15:58 Post subject: Machineguns revisited, with technical fluff (Long) |
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Well, I posted this at the official board, but I am not going to stay there, so I thought I would share, since this took me a lot of work, and I think is interesting, and anyway the game developers just cannot get things right no matter how many times they try
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This question has bothered me since I started playing in 1990.
Why do machine guns have some many shots per ton? Am I supposed to be rolling for how many rounds are used every time I fire it, like one shot use 2d6 rounds or something?
Otherwise it is an ammo explosion waiting to happen!
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Hello, I am back to the Battletech virtual word after years of absence. I saw this post, and by a coincidence, I had just finished my house rules on machine guns, and made a new weapons table with photoshop and a lot of stuff I would like to share with you, I had to type so much stuff is better I start a new thread.
I eventually fixed it when I realized these weren't machine guns, not even 12.7mm brownings, but full bore automatic cannons on the 20mm range, and not only that, they were multibarrelled rotary Gatling guns, just as they were uniformly depicted as such in 3026 readout.
They are not really MGs, but small caliber cannons , primarily and armor piercing weapon, but with the use of explosive ammunition they have some anti infantry capability. I did all the number crunching figuring out ammo weights, likely number of bullets shot per gun, and I reverse engineered what the fluff said.
Standard MG would be a 20mm Gatling gun, like the one on fighter airplanes. 200 shots per ton means 4,000 rounds are carried. Every pull of the trigger fires a 20 round burst in one second. Of the 10 seconds of a turn actually only 1 or 2 seconds would be of actual firing. The rest of the time is weapons cycling and maneuvering and lining up a shot.
Mech armor is small arms proof and impervious to shrapnel and artillery explosions. It would also shrug off 20mm rounds, wich only would make small dents, but the concentrated burst of 20mm rounds hitting a spot the size of a dinner plate would make a significant dent, and with enough ammo and time you can chew through the thickest armor, or hit a breach caused by another weapon, or a weak spot even 20mm rounds can pierce, because Battletech armor is ablative. It doesn't degrade entirely.
In the end it was better to just consider the damage system an abstraction for games purposes.Armor points just reflect the statistical probablity that in the long term, any shot will find a weak spot and get through. 20 points of armor can be penetrated by a single burst from a heavy AC20 or take 10 hits from a Machine gun,
But a Mech with zero armor in a location doesn't mean all the armor has been melted or vaporized. Just riddled with holes that can be easily patched. Holes are tiny and are easily plugged without the need to carry hundreds of tons of armor plating in the logistic train. In fact most mechs could probably repair battle damage with the few square yards of armor plate they carry on them
Coming back to MGs, these being rotary guns, mean they could fire even faster, up to a practical limit of 10 rounds per second per barrel to prevent overheating and barrel wear. The fastest firing conventional MG is the German Spandau MG42 from WWII wich could fire at that stupendous rate, 20 per second, or 1,200 rounds per minute. And that was a rifle caliber MG, a 20mm gun would get much hotter, no single barrel 20mm or 30mm can fire faster than 600 rpm, 10 per second,
Rapid fire rules could be reflected using the Ultra autocannon rules, but these were unsatisfactory, in the end is simpler and more realistic to simply allow them to fire twice, in a round and three times for Light Machine guns , making a to hit roll for every Guns.
Here are my house rules. There would be three types of MGs. (see table below)
Type Short Medium Long Damage Shots/turn Ammo/ton
Light MG 1 2 3 1 x3 400
Medium MG 1-2 3-4 5-6 2 x2 200
Heavy MG 1-3 4-6 7-9 3 x1 100
Technical fluff
Rounds Weight Weight Cartridges
Type Caliber Barrels x Burst (max) Burst Cartridge per ton
Light 15mm 6 20(60) 2.5 kg 125g 8,000
Medium 20mm 4 20(40) 5.0 kg 250g 4,000
Heavy 30mm 3 20 10.0 kg 500g 2,000
Light MG, rate of fire 20 rounds per 1 second burst, ammo 8,000 x 15mm cartridges . This 15mm is hypothetical but keeping in line with the stats it would be exactly half as powerful as the Medium MG round, so every round would weigh 125 grams.
I did the math and these would be roughly equivalent but a bit more powerful to 15mm cannons like the MG151 mounted on the WWII Messerchsmitt Bf109F fighter, of the 14.5mm round used in the Soviet KPV Heavy Machine Gun, wich was a round used originally in an antitank rifle. (the KPV round weighs 65 grams)
This would be the smallest caliber cannon, the difference being that machine guns fire solid bullets, and cannon can fire a round with a substantial explosive filler.
Note that despite the small increment of caliber, these are rounds much more powerful than the standard 12.7mm NATO round, notice that the KPV round has approximately twice the energy of a 12.7 mm And the Battletech 15mm Gun is even more powerful. A Mech can shrugh small arm bullets like rain, but 15mm is the threshold at wich a projectile actually manages to make a dent in armor, or embed in it.
Everytime you pull the trigger you fire 20 rounds, divided into 6 barrels these makes it a confortable 3 rounds per barrel per second. The MG could be spun much faster until firing 60 rounds in one second, 10 per barrel. This would heat the barrels considerably, but since it fires only a turn it pases 9 seconds between each firing that allow it to cool down. Though I suppose at that firing rate, by the time the ammo bin is emptied the barrels would be red hot.
Cutting a long story short, the Standard MG would be a 20mm Vulcan like the one mounted on fighters, but a round substantually more powerful, at 250 gram per projectile.
And a Heavy Machine Gun would correspond with the 30mm GAU8 mounted on the famous A-10 Thunderbolt II tank buster airplane.
Notice there are differences with real world guns. I will address them.
Ranges
Battletech ranges are game abstraction, they were done in a scale of 30 meters per hex to allow for footwork and some maneuvering like a dogfight game. For real effective ranges, assume each hex is 100 meters. Armored combat, due to armor penetration capabilities, ballistic laws and visibility usually does not take place beyond 2000 meters
If Battletech used realistic range hexes, then the game would look like a Napoleonic miniatures wargames, with lines of Mech slowly inching across the table in extended lines while blasting each other. Though large scale battles would look like that, the Battletech game scale represents at most company size engagements, knife fights in an alley between opposing patrols.
Actual ranges are not as important as relative ranges. Of course even a light 15mm MG can fire up to 3.000 meters, not 300 (assuming 1 hex =100 meters) but due to ballistics, it can only penetrate armor at point blank ranges, that is under 300 meters.
Again, the To Hit rolls are an abstraction, targets at longer ranges are harder to hit not because you miss, but because is more probable that your projectiles will have less energy and will bounce off the armor. This is a game simplification for playability, to avoid having variable damage depending upon range. But it reflects that compared to an autocannon, a Battletech MG has very little range.
Game wise, I decided to increase the MG range, because 20 years of gaming Battletech led me to the conclusion that weapons with a range of 3 hexes are practically worthless, and that the Medium Laser was unbalancing because it was too good in comparison with other weapons.
That is why I decided to double the range of the Small Laser to 6 hexes. Since the original standard MG had the same range, is only fair to increase it as well. This allows us to introduce the Heavy and Light MGs, and fit nicely with the actual ballistics.
Notice that even if using fractional accounting, a HMG with a minimum of 0.25 ton of ammo (25) shots, weighs the same as a Medium Laser with the same range, but does only 3 points of damage. The only advantage is heat, and I would still pick the laser as the better weapon.
Fluff
I am assuming the rounds fired by ballistic weapons are likely tungsten (Wolfram) penetrators, because I do not think Depleted Uranium is available in the Battletech universe. Uranium is rare to begin with, and second, it's a byproduct from the nuclear industry. I think nuclear fission became lostech in Terran Hegemony days. Is dirty and messy, and who needs it when you have available fusion power or plentiful fossil fuels? Of course some radioactive industry would have been kept, for producing isotopes for medical and industrial uses, and of course, everybody kept nuclear weapons programs. But I think nuclear fission has become lostech by the time of the Succession Wars. By 3025, the Succesor States don´t even have nukes stockpiled just in case. They were consumed long ago, and no one has bothered to start a Manhattan project again.
Bottom line, I don't think Depleted Uranium (DU) is available in any quantity at all to be used either for armor piercing projectiles or armor. Hell, by 3025 tungsten may be scarce or difficult enough to produce Mechs are shooting at each other with steel projectiles.
This is a very long winded way of telling some people that the GAU 8 Avenger gun is not as awesome as it actually is, and that would complain about it doing a measly 3 points of damage in Battletech. Face the facts, the Heavy MG doesn't fire DU, and the GAU 8 was only effective anyway against obsolete tanks with steel armor, and then only when firing against the thinner armor of the rear sides, and top of the tank. Mech armor from fiction looks basically like Chobham composite armour, only improved.
I also reduced the number of barrels these rotary guns have. Basically for neatness and to explain fluff wise why a HMG can only fire once a turn, by imposing a practical limit of no more than 20 rounds per second per barrel. HMGs have 3 barrels, and Standard MGs four.
Why it so? Because Battletech weapons have to be encased into the armor of the Mech or tank or aerospace craft. In the 20th century, it was a freak shot when a round managed to hit a tank barrel, but in Battletech, with such a density of projectiles, missiles and energy beams, you could lose your weapon systems if they are not armored. Thats why barrels of Mechs look so huge. The Enforrcer autocannon for example, has a bore of about 10 cm diameter. but you have to encase the entire barrel in armor so it end looking like a sea going WWII Cruiser gun in thickness if not length.
Is just a matter of using the minimum to get the job done. By eliminating the superfluous barrels you make the rotary gun more compact, and can encase the entire rotating assembly into a single armored tube. That´s why the Warhammer MG barrels look so big, these weight savings are compensated with other increases. Besides the barrel, you need an armored mantlet or ball mounting to integrate the guns with the armor of the Mech or tank., you do not want a gaping hole in the armor to stick the MG through it wich becomes a weak spot. Add also the ammo feed system, and the electrical or hidraulic systems to traverse and elevate the gun, since they are not in a fixed position.
Anti infantry role:
Basically the MGs are a secondary weapon, something to mount when you have a couple spare tons and can´t find any better use for them. They do have a useful secondary antipersonnel role.
That comes handy, if you use the rules from Max Tech or any other house rules that limit the damage to infantry.
Basically, all Battletech weapons are armor piercing point weapons, that do only 1 damage per shot to infantry. Or practically useless. Missiles are more effective, but my house rule is that they do only half damage, rounding down, because they are imprecise and their explosive load ain´t that great, not to mention shaped charges are not as effective against personnel. And missiles are expensive.
The most effective weapon would be loading the autocannons with explosive shells, but is a waste of ammo. True, a hit from an AC10 burst iring HE s like receiving a direct hit from a heavy artillery salvo , causing 10 casualties. But you only have 10 shots per ton, how much HE can yo carry that is useless against Mechs?
So machine guns are cheap and somewhat effective antipersonnel weapons IF loaded with HE rounds. They fire a modest amount of rounds, so if you fired with Armor piercing, it would be generous to allow they cause their standard damage instead of only 1 point. If you fired HE rounds then concussion and fragmentation would allow you to cause double damage per hit. The Light MG on account of its fast rate of fire would be the most useful weapon against infantry, though the most effective is no doubt the flamethrower.
So if you really want an effective antipersonnel weapon, there's room for another weapon system:
Automatic Grenade Launcher
Type hort Medium Long Damage Shots/turn Ammo/ton
Grenade Launcher 0.125 1 1-2 3-4 5-6 2(4) 1 200
Caliber 40mm, fires 10 grenades with each burst, and each round weighs 500 grams, for a grand total of 2,000 rounds per ton.
Notes: causes 1 point to Mechs but 5 to infantry
For similar reasons as those described above, the present day tendency is to use auto GL instead of MGs. These are big machine guns that fire small 40mm grenades. The advantages they have is that the explosive and fragmentation effect is more effective than firing hundreds of bullets, and that they can engage targets with plunging fire or under cover from grazing fire.
The battletech version is basically an augmented version of such Auto GL as the US Mark 19. Is heavier for the reasons stated for MGs, a GL is lightweight because the grenades are designed with a high-low pressure cartridge wich diminishes the recoil and it is absorbed by the ground through the tripod. In the Mech the recoil would be absorbed by the frame, and it would have a much more vicious recoil. Is more of a miniature autocannon than the pop gun the GL is. It would be helpful to envision it as a slightly larger WWII German Mk108 aircraft autocannon such as mounted in the Me262.
Modern Auto GL are slow firing, this beast fires in a single 1 second burst 20 grenades, at a cyclic rate of 1200 rpm, being single barrrelled it cannot fire as fast. Range is short because even if using full pressure cartridges, the muzzle velocity would be modest. It does damage to armor because the shells are High Explosive Dual Purpose, basically small hollow charges, and though the armor penetration of each round is minimal, one score of them is going to cause some damage. Firing them at a Mech would be a waste though a nice fireworks display. Is effectiveness is against infantry.
Notice the tradeoffs of each weapon for antipersonnel firing. All MGs if firing armor piercing only cause 1 casualty, they simply can't spray the way is done with a rifle calibre machine gun because they do not fire enough bullets, and then again, they cant sweep an area like a infantry MG with is barrel paralell to the ground does.
LMG, less range, more chances to hit, but only 3 points of damage maximum, even if firing HE. The explosive filler in that bullet is too small to have a substantial blast and fragmentation effect, but is useful for setting things on fire or blowing them up
MMG. Equal range, 4 points if firing HE, but have two roll two times.
HMG More range but only does 3 points\ with HE
The 5 points damage of the GL seems a tad high, until you remember each grenade has a 5m lethal radius, and you are firing 10 of them into a 30 hex meter.
The GL could also have other uses, it would be a cheap and effective way of firing incendiary grenades to start fires, or smoke, or flares for night fighting. Nowadays they have even made an IR flare for night fighting, it does not produce visible light but IR radiation that can be picked by Passive IR
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Memento audare semper
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Rudel Gurken
Allisters Light Thunder
Major
Joined: 15-Jun-2005 00:00
Posts: 1470
Location: Germany
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| Posted: 20-Dec-2011 06:49 Post subject: Machineguns revisited, with technical fluff (Long) |
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Very interesting and thoughtfull text!
What you say about armor and damage is exactly that as what i've thought about it.
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Reality is where the Pizza-man comes from!'Gucken, petzen, verpissen!' (Look at it, squeal it, get the hell away from it!) – Motto of the recon troops'Artillery doesn´t know friend or foe! They only know worthwhile targets!‘ – Kuritan Infantrist
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innersphere3050
Federated Suns
Corporal
Joined: 12-Jan-2011 18:43
Posts: 69
Location: United States
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| Posted: 27-Jan-2012 19:57 Post subject: Machineguns revisited, with technical fluff (Long) |
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With these rules it might be worthwhile to mount a machine gun. I like it. I like that they can fire multiple times without risk of jamming....after all they are machine guns
Shooting farther than 3 hexes really helps the cause of the machine gun. both to shoot other mechs and to not have to close with infantry just to use an anti-infantry gun
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Vampire
Free Worlds League
Lieutenant Colonel
Joined: 05-Feb-2002 00:00
Posts: 917
Location: Spain
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| Posted: 03-Feb-2012 13:48 Post subject: Machineguns revisited, with technical fluff (Long) |
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I am glad you liked and found them interesting. Couple small changes that appeared under further playtesting.
The Heavy Machine Gun should cause 1 point of heat. This is of course not from the heat of the firing but from the electrical power consumed in operating the gun and absorbing the recoil that is considerable.
That being said the 1 Heat is a game balance measure to not make everybody switch standard MGs with heavy ones, this is in line with the fluff of the Scorpion Light tank in TRO 3026 wich said 20mm guns are preferable to 30mm due to the higher rate of fire.
The only canon Mechs that would be equipped by default with heavy MGs should be the Crusader and the Phoenix Hawk, both armed with M100 guns, wich in the fluff are the only ones described as "heavy"
Finally after some adjustment, the Grenade Launcher stands at firing 1 time and having an ammo of 100 bursts per ton. Everything else remains the same
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