User:LRichardson/Interpolated Autocannons

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The subject of this article does not contribute canonical content to the BattleTech universe, either because it is not intended to or because it is not an official product.
See the article's section on Canonicity for details.

Authors note: This essay is a presentation of opinion of a volunteer contributor to the BattleTech Wiki project. While an effort has been made to preserve the accuracy of canon material referenced, this essay does not reflect any official position by FASA, WizKids, Catalyst Game Labs, RCW Enterprises or any other party with interests in the BattleTech property. New items and rules proposed here are not canon and are obviously unsuitable for tournament play. All the new weapons presented here are thus non-canon cannons. ;>


Considerable gaps exist in the selection of ranges and damages of autocannon types. Desired damage values are derived. The various types and subtypes of Inner Sphere Autocannon are plotted graphically and interpolated values for 8, 12, 15 and 18 damage are read for standard, LB-X Autocannon and Ultra Autocannon types. Battle values were calculated separately.


A common comment on autocannons as published is that relative to their actual performance, autocannon are over represented in canon designs. AC/10's lack the one hit kill possibility of a gauss rifle, and AC/20's lack the reach. Indeed, the gulf in performance between the 10's and 20's is so wide that it is something of a stretch to see them as part of a continuous spectrum.

The fluff description of autocannons describe them as being put into general classes where the size of a single shell is irrelevant. That is to say an AC/20 may represent 10 shells doing 2 points of damage each all to the same location or it may represent two shells doing 10 damage, or any other combination of values adding up to 20.[1] Personally, this has never been much of a satisfying description as with only a minor exception here and there the rules behave as though a single shot from an AC is exactly that, a single shot. Realistically, insofar as that term applies to a sci-fi game about giant robots slugging it out on 31st century battlefields, autocannon would be possible in a pretty much continuous spectrum of damage values.

Nonetheless, likely for practicality reasons the number of weapon types in the early incarnations of BattleTech were kept limited. Initially there were no "types" of autocannon. The AC was an AC/5 and that was the only type of AC available[2]. With the publication of CityTech the AC/2, AC/10 and AC/20 types were introduced[3]. Even a brief look at the stats for these weapons reveals a strong set of trends. As damage goes up, mass and size go up, heat goes up, range drops, shots per ton drops, ect. With this in mind, I've set about trying to fill in the gaps between autocannon sizes to give a little more variety of choices within the existing technology paradigm. With the trends in the stats for AC's it would seem that as the projectile gets heavier its damage goes up and its range goes down, generally consistent with a single shell being fired with a similar amount of propellant. This essay will assume this to be the case, even though this is directly contradicted by fluff.


Autocannon as a whole are not simply one type of system. There are "standard" autocannon, LB-X autocannon, Ultra autocannon and others. Technical Readout 2750 saw the introduction of the LB 10-X and Ultra AC/5 autocannon[4]. Initially there were only these types of new autocannon but a full range of 2, 5, 10 and 20 point versions of the LB-X and Ultra types were introduced in the Tactical Handbook as what were then known as "Level 3" rules[5]. Later, a new set of LB-X and Ultra autocannon were published in BattleTech Master Rules with slightly altered stats[6]. This second publication listed these types as being "Level 2" rules, suitable for tournament play[7]. Each of these subtypes has a base set of trends that hold only within that type. As such, all of these ought to be handled separately as families of weapons for analysis. For the sake of completeness, all five of these families will be analyzed, Standard, Ultra, Ultra (THB), LB-X and LB-X (THB).

With an interpolative method, in theory a design could be made for every single integer value between the published types. For the sake of brevity however some arbitrary points have been selected that ought reasonably fill in the gaps in the published values. Between an AC/2 and an AC/5 there are relatively few values, so no midpoint was selected. Between an AC/5 and an AC/10 there is more room. 6 and 9 damage were considered to be too near 5 and 10 damage respectively and were not considered. This left 7 and 8 as the available points. For essentially aesthetic reasons 8 was chosen as preferable as 8 damage is in line with the damage a large laser does. The choice of 8 is though otherwise arbitrary. Between 10 and 20 damage first there is the obvious midpoint, 15 damage and this was selected. Between 10 and 15 the choice was between 12 and 13. 12 damage is a significant threshold in that the total of the maximum armor and structure of a `Mech's head is 12. Assuming the ability of a one shot kill is the desired result doing more than 12 damage is excessive.

Graphical Results[edit]

Published autocannon data were entered into an OpenOffice spreadsheet and plotted as a series of XY line graphs. Smooth lines were chosen to reflect the non linear nature of most of the relationships in the data. No regression analysis was performed. Interpolated values were read by eye and manually adjusted somewhat to a normative best fit with respect to rounding and an ad-hoc assessment of desired meaningful differences between types. As heat, mass and critical spaces all trend upwards and are numerically similar in magnitude these values were plotted together. For similar reasons ranges, battle values and prices were grouped. This is simply for ease of visual inspection. The rendered graphics are presented here.

Standard AC[edit]

Standard AC Interpolation Results

LB-X Autocannon[edit]

(as published in BattleTech Master Rules)

LB-X AC Interpolation Results

LB-X Autocannon (THB)[edit]

(as published in Tactical Handbook)

LB-X AC (THB) Interpolation Results

Ultra Autocannon[edit]

(as published in BattleTech Master Rules)

Ultra AC Interpolation Results

Ultra Autocannon (THB)[edit]

(as published in Tactical Handbook)

Ultra AC (THB) Interpolation Results

Images generated via screen capture.

While plots shown were made of battle values and interpolated points selected from the graph, explicit calculation of BV is available through Heavy Metal Pro. An example calculator can be found at

The explicit calculated values are used below in lieu of the interpolated estimation of BV from the data seen here.


Interpolation of values for the various lines of autocannon do not seem to reveal a "sweet spot" where the AC's can be seen to overcome perceived shortcomings. The standard AC's especially remain essentially obsolete save for their low cost and ability to use specialty ammunition. The Gauss Rifle, at 15 damage, 22 range and 15 tons still outclasses all of the 15 and 12 damage autocannons derived here. The mass of the Gauss Rifle is still greater than all of the autocannon types shown here however and the 15 and 12 point models, especially the ultras, are closer to being competitive to the Gauss Rifle in having the possibility to destroy most Mechs in a single hit with a headshot. In comparison to another, independently derived, AC/15, LB 15-X AC and Ultra AC/15, the values presented here are quite similar to but slightly lower performing in their stats.

These weapons present very little new material to the BattleTech universe, require no new rules or understanding and are relatively conservative in their abilities. The most significant entry in the line is the 12 point versions in their headshot ability, though this is not a huge benefit compared to other extant weapons in BattleTech. Thus, these items should be an easy fit into most any BattleTech game in a non tournament setting with little or no disruption to the status-quo game balance.

The trend lines presented above can just as easily be used to further generate AC types for all integer values from 3 to 19 damage. Extrapolation above 20 points is not recommended as linearity of trend lines is not evident nor has any other analysis been done to suggest any other functional extrapolative model. Such extrapolation has significant potential to cause game balance concerns beyond the scope of this study.

Tabulated Results[edit]

These tables list the result of the graphical interpolation of the plotted trendlines of canonical autocannon weapon stats. Battle Value and Ammo Battle Value are BV1 and are not interpolated graphically but are instead calculated via Heavy Metal Pro version 5.22 R03. Calculated results for both Tactical Handbook and Total Warfare versions of LB-X and Ultra autocannon have been listed for completeness. The results are listed as being level 1, 2 and 3 in accordance to the types that they were generated from. Strictly speaking, if using the rules levels, all custom weapons are "Level 3" rules, that is to say optional rules to be used at players discretion by mutual agreement. The rule levels are left as they are simply to infer that the general performance of the weapon types are compatible with other weapons available at that level. Furthermore, the whole classification of rules levels has itself been eliminated from Total Warfare. Again, the rules levels are left here only for the sake of comparison.

Standard Autocannons[edit]

Type Level Heat Damage Min Range Short Range Med Range Long Range Mass (Tons) Critical Ammo/Ton Weapon Cost Ammo Cost Weapon BV Ammo BV
Autocannon/8 1 2 8 1 5 11 16 11 6 12 175000 5500 105 13
Autocannon/12 1 4 12 0 5 9 14 12.5 8 8 220000 6500 165 21
Autocannon/15 1 5 15 0 4 8 12 13 9 7 250000 8000 178 22
Autocannon/18 1 6 18 0 3 7 10 13.5 9 6 280000 9000 179 22

LB-X Autocannons[edit]

Total Warfare[edit]

Type Level Heat Damage Min Range Short Range Med Range Long Range Mass (Tons) Critical Ammo/Ton Weapon Cost Ammo Cost Weapon BV Ammo BV
LB 8-X AC 2 1 8 1 6 13 19 10 5 12 340000 11000 125 16
LB 12-X AC 2 3 12 0 6 11 17 12 7 8 445000 13500 201 25
LB 15-X AC 2 4 15 0 5 10 15 13 8 7 495000 26000 222 28
LB 18-X AC 2 5 18 0 4 9 13 13.5 10 6 555000 18500 232 29

Tactical Handbook[edit]

Type Level Heat Damage Min Range Short Range Med Range Long Range Mass (Tons) Critical Ammo/Ton Weapon Cost Ammo Cost Weapon BV Ammo BV
LB 8-X AC (THB) 3 2 8 1 7 13 19 10 5 12 350000 12000 126 16
LB 12-X AC (THB) 3 3 12 0 6 11 16 12 7 8 445000 14000 193 24
LB 15-X AC (THB) 3 4 15 0 5 9 14 12.5 8 7 505000 19500 206 26
LB 18-X AC (THB) 3 5 18 0 4 8 12 13.5 9 6 560000 26000 213 27

Ultra Autocannons[edit]

Total Warfare[edit]

Type Level Heat Damage Min Range Short Range Med Range Long Range Mass (Tons) Critical Ammo/Ton Weapon Cost Ammo Cost Weapon BV Ammo BV
Ultra AC/8 2 3 8 0 6 11 19 12 6 12 275000 11000 169 21
Ultra AC/12 2 5 12 0 6 11 17 13.5 7 8 355000 13000 284 36
Ultra AC/15 2 6 15 0 5 10 14 14 8 7 405000 16000 302 38
Ultra AC/18 2 7 18 0 4 8 12 14.5 9 6 450000 18000 302 49

Tactical Handbook[edit]

Type Level Heat Damage Min Range Short Range Med Range Long Range Mass (Tons) Critical Ammo/Ton Weapon Cost Ammo Cost Weapon BV Ammo BV
Ultra AC/8 (THB) 3 3 8 0 7 14 21 11 6 12 330000 12500 196 24
Ultra AC/12 (THB) 3 5 12 0 7 13 20 12.5 8 8 450000 17500 335 42
Ultra AC/15 (THB) 3 7 15 0 6 12 17 13.5 9 7 510000 22000 365 46
Ultra AC/18 (THB) 3 9 18 0 5 9 14 14.5 10 6 565000 27000 351 44


  1. Tech Manual, p. 207
  2. BattleDroids Manual, p. 20
  3. CityTech 1st Edition, p. 34
  4. Technical Readout 2750, p. 8
  5. Tactical Handbook, p. 54-55
  6. BattleTech Master Rules, p. 115
  7. BattleTech Master Rules, p. 3