Production information
Model JR7-31[1]
Class Light
Technical specifications
'Mech type Inner Sphere BattleMech
Mass 35 tons
Armor Ferro-fibrous[2]
Engine 245 XL engine[2]
Heat Sinks 11 double[2]
Speed 118.9 km/h
BV (2.0) 1,398

The Rattlesnake BattleMech was created for the MIIO by Dr. Robert Madson as part of Project Trapdoor sometime after 3042.[3][1]

It is derived from the Jenner to the point of ultimately being (arguably) just an upgrade variant of it, and even shares the Jenner's JR7 alphanumerical code. However, for the purpose of the Sarna.net BattleTechWiki it is considered a separate design and not a mere variant because it was treated as such in its original writeup.


Originally published in Issue #21 of BattleTechnology magazine, the Rattlesnake was then implicitly considered canon but was downgraded to apocryphal when it was clarified that periodicals did not meet the criteria for canon and thus default to apocrypha.

With the Vengeance Games serial published in the explicitly canonical Shrapnel magazine, the Rattlesnake regained its canon status.


The Rattlesnake was an upgrade to the Jenner, designed to make use of cutting-edge technology recovered from the Helm Memory Core while outwardly appearing as a standard Jenner.[3][1] As far as can be established, they were created by refitting existing Jenners as opposed to being built in a proper factory. As part of Project Trapdoor, the Rattlesnakes were deployed with an eye to sowing confusion and uncertainty among Draconis Combine forces, and they were also used for MIIO black ops. One mission which involved the destruction of a Warhawk (Masakari) OmniMech by Rattlesnakes was embellished and altered to an unspecified degree before being published as part of the psyops.[3][1] As of 3084 the 'Mech was widely regarded as an urban legend.[3]

Stated quirks for the Rattlesnake are "Rugged (2)" and "No/Minimal Arms".[1]

It is not known how many Rattlesnakes were built, but even at the height of Project Trapdoor, no more than 20 to 30 were deployed.[1] Operation Trapdoor was discontinued after around seven years,[1] and while the Trapdoor 'Mechs continued to be used, only few of them survived into the Jihad era.[1]

Weapons and Equipment[edit]

The original JR7-31 Rattlesnake from the 3040s reportedly featured cutting-edge technologies including Ferro-fibrous armor, an XL Engine and a Guardian ECM Suite. Its main armament are seven medium lasers. Its 11 double heat sinks are only just capable of keeping its heat in check. Two jump jets were added to the original five, for a total of seven.

No specific manufacturers are known for any of the components, probably because each Rattlesnake was effectively hand-built instead of a formal standardized production. Given that it is essentially a rebuild of the Jenner and deliberately trying to mimic the original design, it stands to reason that all components that it shares with the Jenner would in fact be the original Jenner components (by the respective manufacturers).

Apocryphal Content Starts

The information after this notice comes from apocryphal sources; the canonicity of such information is uncertain.
Please view the reference page for information regarding their canonicity.

According to the BattleTechnology writeup, which is said to be rooted in fact yet at the same time edited with the intent to deceive, the Rattlesnake was built by "Phoenix Industries" and features a Phoenix JR35 chassis, a Phoenix 245 XL engine, Phoenix J245 jump jets, Phoenix Cuirass 112 Ferro-Fibrous armor, Hammerstorm Mjolnia-5 {sic} medium lasers, a Hammerstorm Mjolnir-3 small laser, a Hammersorm Hugin Mk XIV {sic} communication system and a Hammerstorm Munin Mk IX targeting/tracking system.

Any of this may or may not be accurate, given the peculiar status of the only source.

Apocryphal Content Ends


  • JR7-31P 
    A variant that came up in 3043[citation needed] replaced the ECM suite with a head-mounted C3 Slave unit and a small laser in the left torso. This variant is the original Rattlesnake as it was presented in the BattleTechnology magazine. It would eventually be put back in production by the time of the ilClan era.[1] BV (2.0) = 1,323[4]

Custom Variants[edit]

Related designs[edit]


  • The cover of Shrapnel, issue #9, depicts Gideon Wozniak's Rattlesnake in battle, a scene from the story found in this issue.
  • The original BattleTechnology magazine writeup (comprising of the short story Snake Dance, scenario "Snake Rattle & Roll", and Rattlesnake technical details and game stats) was canonically alluded to as an in-universe publication that was rooted in fact yet "did not ring true", having been deliberately published as part of the Project Trapdoor psyops with the aim to mislead and deceive. The writeup thus straddles the line between apocryphal and being a canon rumor.

See also[edit]

  • Shrapnel #9: Fight with Confidence (Rattlesnake Variants) - Rattlesnakes


  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Rattlesnake II writeup in Shrapnel magazine, issue #9, pp. 53-55
  2. 2.0 2.1 2.2 Rattlesnake record sheet in Shrapnel magazine, issue #9, p. 58
  3. 3.0 3.1 3.2 3.3 3.4 Vengeance Games, part 2 (in: Shrapnel magazine, issue #7)
  4. Official Shrapnel-9 Record Sheets publication (digital), freely available from the CGL website.
  5. Shrapnel Issue 9, p.89-94: "RSN-1 Rattlesnake II"