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Author Topic: Why do Autocannon have a minimum range?  (Read 15345 times)

Nebfer

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Re: Why do Autocannon have a minimum range?
« Reply #60 on: 11 January 2012, 21:11:27 »
I actually think this has a lot to do with this:

Don't forget the ranges that these same weapons get when tacked onto an Aerospace craft, and the flight times which suggest "Ludicrous Speed!!!" as the velocity at which they travel.

Projectiles in BT, in order to get the kilometers space ranges in the 10 or less (most obviously less) seconds one can expect it to fire and still hit the target on time, are moving at insane speeds that modern ballistic engineers only dream about.

BT Missiles aren't armed while in the tubes. They arm themselves in flight. I imagine that inside the first 6 hexes, they've only been in the air the smallest fraction of a second.

How does this apply to ACs? Have you notice how they group their damage? It's all or nothing with an AC. At least with Missiles, you get partial cluster sizes. With ACs, it's full damage for a group, or it's a miss.

While I'm one to laud the accuracies inherent in a futuristic weapon tied to a futuristic targeting system, ACs do have the high recoil to deal with. The larger class ACs have massive recoil to handle for the shear power they're pumping out inside a second or two. It's all they can do to keep the AC on a large target, let alone expect it to have all its shells slam home on a specific area on that target.

I'm one that follows the idea that if you don't group the shells or the shot well enough, the armor, or the defensive stance of the Mech combined with the armor, deflects the shots 'harmlessly'. If you spread your shots across multiple locations, you just got a miss. In game terms you don't get to roll for location and color in armor or internal structure boxes.

If the AC, and the Mech itself, are fighting the recoil of the weapon, then it seems like a true hit is next to impossible. But, it happens with some regularity. Why? Because I think there's more to the ammunition ACs use than is told to us.

I posit that BT ballistic munitions are smart rounds, that home in on a designated target via controlled spin or fin stabilization, or whatever. If a weapon groups its shots well enough, they'll all home in and do the damage, otherwise, they spread out too far and do nothing more than 'scratch and burn the paint'.

The lighter Autocannon classes are dealing with the same recoil. Sure, they're not trying for massive groupings, but they are trying for range, and to get that range, the rounds have to pour out the barrel at a greater velocity. Some limitations could also  be attributed to the size of the rounds, as well. But, that extra fraction of a second is all that is needed to keep the spread from homing in successfully.

The longer I play, the more I try to mentally visualize what's actually happening, the more I come to believe it's not any one thing that allows for a certain aspect to happen. It usually ends up being a combination of factors which may or may not overlap with other game aspects.

Well to me LBXs firing Cluster seem to be using large scale AHEAD rounds, basically advanced proximity fuzed rounds, smiler to the Airburst ammo used by the XM-25 (speaking of which IIRC the AFFS also has this for rifle & shotgun ammo in the RPG).

Assuming B-tech autocannons are flinging rounds at very high speeds, one way to improve velocity is to deal with a light weight shell fitted with a shoe to fit to the barrel, Sabot rounds (I.e. APDSFS rounds) which dose not need to be only used on kinetic rounds HEAT rounds also use it (I.e. M830A1). Though Autocannon projectiles are an odd item, their fluffed as being HEAP, but they also are often mentioned as having DU tips, the closest rounds I can find that would seem to be what B-tech uses is the Mk 211 Raufoss (listed as HEIAP -High Explosive Incendiary Armor Piercing).

One technically dose not even need to go into capital scale to see evidence of high speed projectiles.
AA shooting can show this.

B-tech ASFs can be traveling at a velocity of 12, or 2,160kph (mach ~1.8), now I never heard of a good anti aircraft gun that fired shells that traveled at velocity's slower than the intended targets, and most successful guns seem to fire shells that are easily three to six times faster than their intended targets (I.e. the Flak 18 fired rounds at ~800m/s it's targets often flew under 200m/s), this is still largely true today, most real world AA guns still fire rounds in the 1,000m/s range but the "targets" still often fly under 300m/s. As B-tech Autocannons are considered some what effective in this role, it would seem to be that the rounds they fire are noticeably faster than their targets.

innersphere3050

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Re: Why do Autocannon have a minimum range?
« Reply #61 on: 11 January 2012, 22:37:25 »
There is no good reason for minimum ranges on autocannons....or any other direct fire weapon.  Arming of LRM warheads is the only one that makes sense.  We have always played with no minimum ranges for direct fire weapons.  This helps the AC/5 in a 3025 game.

But nothing can help the horrible AC/2

willydstyle

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Re: Why do Autocannon have a minimum range?
« Reply #62 on: 12 January 2012, 00:59:40 »
Of course no minimum on direct fire weapons also helps the PPC, which really doesn't need the help.

MoneyLovinOgre4Hire

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Re: Why do Autocannon have a minimum range?
« Reply #63 on: 12 January 2012, 01:20:49 »
Or Gauss Rifles, which really don't need the help.

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chanman

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Re: Why do Autocannon have a minimum range?
« Reply #64 on: 12 January 2012, 02:37:01 »
Or Gauss Rifles, which really don't need the help.

Or HGR which *do*

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Re: Why do Autocannon have a minimum range?
« Reply #65 on: 12 January 2012, 02:40:47 »
Really?  I've never found that to be the case.

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Nightlord01

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Re: Why do Autocannon have a minimum range?
« Reply #66 on: 20 January 2012, 09:15:04 »
The only reason I could think of not yet mentioned is part of tech base. During the SW, the houses lost a lot of technology, including most of the extant weapons technology. Most components were produced at a few massive factories, all of which ran by automation, and when they broke, no one knew how to fix them.

Given that the Star League were the masters of standards, wouldn't it be pretty safe to assume that everything was made to a standard pattern? Even if there were multiple manufacturers, they may have all made their weapons to the same standard, with only layout or mounts being different.

Therefore, if all AC2s are made to a standard pattern, then they all have the same foibles, same with all AC20s. This would account for variation in more recent developments as well, as none of these were made from a standard pattern.

ApokalypseTest

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Re: Why do Autocannon have a minimum range?
« Reply #67 on: 20 January 2012, 09:45:15 »
While we are at it:

Why do heavier ACs have less range than lighter calibers?

Also: Why does the Heavy Gauss rifle have this loss of damage over distance but the normal Gauss doesn't? The heavier shells should have a better surface to volume ratio and fly further...

I find the tracking argument as feasible or unfeasible as any number of points in BT - why do people always start with ACs instead of the hundreds of other obviously unrealistic issues? Why the AC?

Erkki

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Re: Why do Autocannon have a minimum range?
« Reply #68 on: 20 January 2012, 10:13:03 »
Hello everyone. Some thoughts of mine:

LRM minimum range: warhead arming is the fluff explanation. A more probably/realistic reason is probably that like many RL missiles, the BT LRMs are actually 2-phase. First phase rapidly accelerates the missile to very high speed and the second(IRL usually also smokeless) phase keeps it at its speed. Finally the 2nd phase runs out and missile will burn Ek while maneuvering to target. Minimum range would be the range at which the 1st phase ends and the missile becomes most maneuverable.

AC minimum range: fluff explanation is the weapon turning/aiming. I dont think the shell(HE) explanation is valid: gyroscopic shell arming and self-destruction was used in the 1940s already, meaning the shell would get armed while it left the barrel by a 100% mechanical system using springs... Only explanation I can make up(that also explains the grouped or "slug" damage) is that the ACs too actually shoot some kind of self-propelled or semi-self propelled ammunition one at a time while barrels are still rifled and shells rotate to be more accurate.

On gauss: what if it doesn't shoot a Ek penetrator but a HE shell? It would explain the shell not losing its destructive power over range.

Of course there are still are more questions left... :)

ApokalypseTest

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Re: Why do Autocannon have a minimum range?
« Reply #69 on: 20 January 2012, 11:19:51 »
Point with Gauss is that it definitely uses a kinetic penetrator according to all fluff sources - and at this point the whole concept of the Heavy Gauss losing steam just breaks down (unless the regular one would too...)


monbvol

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Re: Why do Autocannon have a minimum range?
« Reply #70 on: 20 January 2012, 12:13:42 »
See problems no matter how you approach it.

The LRM issue is why I prefer minimum range penalizing the cluster hit chart instead of the to hit number.  It meshes better with any of the plausible explanations.

Gauss of any variety as have been pointed out fire kinetic penetrators.  No rocket assist.  Nothing that explains why they have a minimum range, or why it isn't worse than the AC's minimum range because that barrel has to be much heavier and longer than an AC-5's.  Nothing that explains why the Heavy loses damage so fast.

ACs, as pointed out fusing has had this problem worked out since the 40's and I do have solid memories of some ACs firing pure depleted uranium ammo, not some tipped HE hybrid.  I just can't remember which novel that was and thus what mech.  Barrel weight/length breaks down too.  All you have to do is look at the Jagermech's art from TRO-3025 or the Rifleman from original TRO-3025.  Their other arm mounted weapons clearly by the artwork share at least one axis of rotation if not both(vertical and horizontal).  So why don't the Rifleman's Large Lasers share the minimum range of the AC-5s on the same arm?  Or the Jagermech's AC-5's take on the AC-2's?

Daemion

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Re: Why do Autocannon have a minimum range?
« Reply #71 on: 20 January 2012, 13:41:30 »
Point with Gauss is that it definitely uses a kinetic penetrator according to all fluff sources - and at this point the whole concept of the Heavy Gauss losing steam just breaks down (unless the regular one would too...)

Actually, a lot of people point out that the ferrous nickel alloy that Gauss munitions are made of are not sturdy enough to do the job of a kinetic penetrator. If gauss munitions are fired at the speeds suggested by even the old AT1 space game, then it's most likely the gauss projectile is turned into a ball of highly reactive atoms, and vaporizes when it hits the target. Again, with the speeds involved, it's possible that the round isn't quite to that physical state while inside the minimum range of the gauss, and will just as likely shatter harmlessly as atomize the location struck.

Now, this might also explain the Heavy Gauss, too, as it loses a lot of its mass in its short flight duration, with loose atoms being stripped away by atmosphere or distance, depending on if you're on the ground or in space.

It's a suggestion, but obviously doesn't hold up when you bring in ground engagements in vacuum environments.

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Nebfer

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Re: Why do Autocannon have a minimum range?
« Reply #72 on: 20 January 2012, 13:58:08 »
While we are at it:

Why do heavier ACs have less range than lighter calibers?

Also: Why does the Heavy Gauss rifle have this loss of damage over distance but the normal Gauss doesn't? The heavier shells should have a better surface to volume ratio and fly further...

I find the tracking argument as feasible or unfeasible as any number of points in BT - why do people always start with ACs instead of the hundreds of other obviously unrealistic issues? Why the AC?
Why the AC I would think it's likely one of the more obvious ones, and one of the few to have a some what analogous weapons system in real life.

Heavy Gauss I would think as an attempt to make it less powerful than it should be (25 damage at ~20 hexes, would make for a powerful weapon). And the fact that TPTB have a nasty habit of making the next generation of weapons more specialized and or have weird quirks, rather than out right better than the last generation. So explaining it would be impossible, I believe even in universe it was mentioned as puzzling. Though the novels have this strange habit of referencing Gauss Slugs as large Nickel-Iron cannon balls.

As for the range differences, Well like the minimum range theirs a few options, one is reduced propellent charge (and reduced MV) resulting in the Heavier guns having less range. Another is accuracy, under the assumption that in order to do damage requires autocannons to be quite accurate, And due to their having less recoil being produced than the heavier ones, lighter ACs have a longer effective range. Again it could be a mix of the two...

As for the tracking concept, theirs not one real good explanation for why ACs have a minimum range, it could be a mix of reasons, applied at different times on different mechs.

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Re: Why do Autocannon have a minimum range?
« Reply #73 on: 20 January 2012, 14:25:57 »
What I'd personally like to see with regards to the HGR and iHGR is for them to be combined into one weapon some time in the future, using the damage of the iHGR with the mass of the HGR.

I'm doubtful that it will happen, but it would be nice.

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A. Lurker

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Re: Why do Autocannon have a minimum range?
« Reply #74 on: 21 January 2012, 06:49:55 »
Why the AC?

Because people like the idea of having big loud honkin' guns on their war machines, yet in actual terms of game mechanics autocannons are generally considered to suck next to energy weapons, missiles, and in a pinch Gauss rifles. Instant motivation to try to "fix" them right there.

willydstyle

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Re: Why do Autocannon have a minimum range?
« Reply #75 on: 21 January 2012, 12:47:29 »
Because people like the idea of having big loud honkin' guns on their war machines, yet in actual terms of game mechanics autocannons are generally considered to suck next to energy weapons, missiles, and in a pinch Gauss rifles. Instant motivation to try to "fix" them right there.

When not using Clan Tech, I actually find the AC10 and LB 10X to be pretty comparable to the other tech in the era.  For example, two PPCs and 10 heat sinks (to make them heat efficient) in intro-tech does 20 damage, weighs 24 tons, and has a bit more range  on the AC10.  A PPC, AC10, 1 ton of ammo, and 3 heat sinks in intro-tech does 20 damage, weighs 23 tons (so 1 ton less), has an explosive component, has one gun with slightly less range, but no minimum range will often offset that problem.  The AC10 is a bit of a tradeoff, as it allows a mech that has reached its heat capacity with energy weapons to be slightly more weight efficient as you add more guns, but then has an explosive component.

The LB 10-X similarly compares favorably to ERPPCs.  With DHS, two ERPPCs and an extra 5 heat sinks weighs 19 tons, but finding the critical space for all those heat sinks can be a problem, especially if you're using endo steel or ferro-fibrous (however, they can be wonderful crit-packing!).  An ERPPC and an LB-10X with no additional heat sinks, but two tons of ammo weighs 20 tons, so you're losing out a little on the weight-efficiency department, but you gain wonderful, wonderful cluster ammunition. Being able to crit-seek at 18 hexes is just beautiful.

monbvol

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Re: Why do Autocannon have a minimum range?
« Reply #76 on: 21 January 2012, 12:58:53 »
I'd still rather have the 2xPPCs.  Sure it may weigh more to have total heat efficiency but if I fore go that and use reasonable firing discipline I can achieve a lot more on a Mech or ASF.  The AC-10 can be used as an okay secondary weapon but I haven't seen a Mech where it is used as a primary weapon where the Mech wouldn't be better off replacing it with something else.  As it exists the AC-10 does have a useful niche, it can be a fantastic main gun on a combat vehicle.

willydstyle

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Re: Why do Autocannon have a minimum range?
« Reply #77 on: 21 January 2012, 13:14:51 »
I'd still rather have the 2xPPCs.  Sure it may weigh more to have total heat efficiency but if I fore go that and use reasonable firing discipline I can achieve a lot more on a Mech or ASF.  The AC-10 can be used as an okay secondary weapon but I haven't seen a Mech where it is used as a primary weapon where the Mech wouldn't be better off replacing it with something else.  As it exists the AC-10 does have a useful niche, it can be a fantastic main gun on a combat vehicle.

If I'm designing a mech with intro-tech, I'd rather have: PPC, AC10, Medium Laser than two PPCs, because you get more total damage and an extra useful weapon to cover the minimum range on the PPC.

monbvol

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Re: Why do Autocannon have a minimum range?
« Reply #78 on: 21 January 2012, 13:41:29 »
When you have the tonnage the 2xPPCs will perform better, especially if you tweak the number of additional SHS to trade in Medium Lasers.  Keep in mind though I'm one of those screwball players who doesn't consider it automatically a bad thing to lose movement due to overheating.

If not then yeah the AC-10 in that sort of setup does work well as a secondary weapon.

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Re: Why do Autocannon have a minimum range?
« Reply #79 on: 07 April 2012, 17:38:15 »
One thing with autocannons is that they are not all the same thing, the AC20 on a Victor, a Hunchback, and on a Demolisher are all different completely different systems presumably using different ammo so the listings are for a kind of generic class of weapon rather than a specific kind of gun.  In the Gray Death series it is mentioned that the Victor and the Marauder use the same ammo in their cannons, but the Victor fires them in short fast bursts. Another book (I forget which book or even which mech they refer to specifically unfortunately) describes an ac20 that is a low velocity grenade launcher scaled up for mechs.

It is true that PPCs perform better for the tonnage than most autocannons, though the AC2 is handy for drawing units out of certain types of cover by plinking at the defenders beyond the range of their weapons.

rlbell

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Re: Why do Autocannon have a minimum range?
« Reply #80 on: 08 April 2012, 11:19:04 »
There is no good reason for minimum ranges on autocannons....or any other direct fire weapon.  Arming of LRM warheads is the only one that makes sense.  We have always played with no minimum ranges for direct fire weapons.  This helps the AC/5 in a 3025 game.

But nothing can help the horrible AC/2

Numbers, careful aiming, extra range brackets, allowing mechs with multiples of the same weapon to use the Strat Ops bracket fire rules (it seemed like a good idea*), and defending a hardened building against mechs marching across a dropship landing field (featureless waste of pavement over a hundred hexes across) go a long way to making the AC/2 a terror.  The assault looked like it might get beaten back, before things got to the minimum range and the defenders were routed.

* I am running a campaign where the players are sent into the sharp end when things are going wrong.  The rebels have more mechs than pilots, and they are each a 100t battlemech, but 8x AC/2's on a 2/3/0 chassis does not equate to an assault mech, even if the armor is maxed.  The B4S Pom-pom was an infantry support and AA mech, and was probably obsolete when it was built to support a doctrine that tried to keep large infantry formations relevant.  I selected a group of optional/house rules to make them a potential threat.
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massey

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Re: Why do Autocannon have a minimum range?
« Reply #81 on: 08 April 2012, 12:14:14 »
AC-2s aren't the greatest weapon, but in 3025 they are okay.  Longest ranged weapon in the game, great range brackets, and they're fighting opponents that don't have that much armor.  Besides weapons like the Clan ER Large Laser, what really hurt the AC-2 was Endo Steel, because it gives players a bunch of extra tons that almost immediately goes to armor.  Add to that rules changes to make vehicles more survivable and the AC-2 sees its role disappear.

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Re: Why do Autocannon have a minimum range?
« Reply #82 on: 08 April 2012, 13:43:19 »
AC-2s aren't the greatest weapon, but in 3025 they are okay.  Longest ranged weapon in the game, great range brackets, and they're fighting opponents that don't have that much armor.  Besides weapons like the Clan ER Large Laser, what really hurt the AC-2 was Endo Steel, because it gives players a bunch of extra tons that almost immediately goes to armor.  Add to that rules changes to make vehicles more survivable and the AC-2 sees its role disappear.

And I'll counter that statement with this one:

Two points that hit will remove more armor than 30 that miss.   The real problem with the AC/2 is most of the platforms it's installed on:

Slow, and limited.

The best platforms for AC/2 employment are vast and use the VTOL hit tables-the reason is that that 2 point weapon can, on a quick moving unit, one not hampered by terrain restrictions, in the right hands hit all day, while NOT being hit in return.

It's your range brackets-the AC/2's Medium overlaps with quite a few bigger hitters' LONG range, and on a fast platform that uses its high cruise speed, that ends up putting the other guy at 9 before he adds gunnery to return fire, while the VTOL's running 7's and 8's (or less, with PA).

Hitting MATTERS.  Any weapon that helps your side hit without taking hits, is a net positive to winning the fight.

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Re: Why do Autocannon have a minimum range?
« Reply #83 on: 08 April 2012, 15:10:02 »
Well said, Cannonshop.

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monbvol

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Re: Why do Autocannon have a minimum range?
« Reply #84 on: 08 April 2012, 15:28:53 »
And that's why I give grudging respect to the AC-2.  The sheer range means if you don't play on postage stamp sized maps it can be a very useful long haul weapon.  I'd still love to see it weigh less but I still respect the range.

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Re: Why do Autocannon have a minimum range?
« Reply #85 on: 08 April 2012, 18:02:09 »
I don't agree with that argument. Weapons are not built with the best of everything for every situation. Designers often make compromises to help weapons excel in one area at the expense of others.
i've just considered it a firmware 'feature'. same basic flavor as cray's thoughts. AC2 and 5 are designed as complete packages for long range solutions.

my house rule is that any ac2 or 5 can be switched to its 'light' stats in the end phase.