< Autocannon(Redirected from GM Whirlwind)
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Production information
Type Ballistic (Direct Fire)
Tech Base Inner Sphere
Year Availability 2250 (TH)[1]
Technical specifications
Heat 1[1]
Damage 5[1]
Minimum Range 3[1]
Short Range 1-6[1]
Medium Range 7-12[1]
Long Range 13-18[1]
Tons 8[1]
Critical Slots 4
Ammo Per Ton 20
Cost (unloaded) 125,000
Ammo Cost (per ton) 4,500[1]
BV (1.0) 70
BV (2.0) 70[2]
5 (Ammo)[2]
9 (Ammo)[2]


The Autocannon is a direct-fire ballistic weapon, firing HEAP (High-Explosive Armor-Piercing) rounds at targets either singly or in bursts.

Different manufacturers and models of autocannons have different calibers (25mm-203mm) and rates of fire. Due to this, autocannons are grouped into generic "classes" of autocannons with common damage ratings, with Autocannon/5s usually having a long range with a small to moderate damage level.

An example of the rating system: the Crusher Super Heavy Cannon is a 150mm weapon firing ten shells per "shot", while the Chemjet Gun is a 185mm weapon firing much slower, but causing higher damage. Despite their differences, both are classified as Autocannon/20s due to their damage output.

An Autocannon/5 can use special munitions to increase its effectiveness.


Designed for the Terran Alliance, the prototype version of this cannon was among first autocannons ever made. It first appeared in 2240[3] and was designed to improve the Alliance's military arsenal cope with newer armor being introduced during the time.[1] Examples of the Prototype AC/5 being used was on the Saturn-Class Patrol Ship in 2243.[4]


The Autocannon/5 is manufactured on the following planets:

Brand Planet Company Used by References
Armstrong J11 Al Na'ir
Scarborough Manufacturers
Scarborough Limited
United Outworlders Corporation
 ??? [citation needed]
Defiance Type J Hesperus II Defiance Industries  ??? [citation needed]
Deleon 5 Kalidasa Quikscell Company  ??? [citation needed]
Mydron C Bithinia Bithinian Ballistics  ??? [citation needed]
Pontiac Light Sterope Sterope Defense Industries  ??? [citation needed]

General Motors Whirlwind[edit]

Famously mounted on the General Motors Marauder BattleMech, this autocannon fires 120mm shells in three round bursts.[5]

Manufactured on Manufactured by Typically used in References
General Motors
TharHes Industries
Marauder [citation needed]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 TechManual, pp. 207-208, "Autocannons"
  2. 2.0 2.1 2.2 TechManual, p. 317, "Inner Sphere Weapons and Equipment BV Table"
  3. Interstellar Operations, p. 217 Additional Alternate Era Weapons and Equipment - "Prototype AC/5 introduction year noted in Table."
  4. Experimental Technical Readout: Primitives, Volume 2, pp. 14 & 31 "Saturn Patrol Ship"
  5. The Price of Glory (PDF Edition), p. 8