’Mech Manual: Thunderbolt TDR-7M

The Thunderbolt TDR-7M was introduced in 3049 by Earthwerks in the Free Worlds League. It was the first upgrade of the Thunderbolt to make use of recovered Star League technology. Earthwerks kept the design close to that of the TDR-5S, but the improved technology made the new model a more capable weapon.

During the Clan Invasion, the TDR-7M was available to all of the nations and mercenaries of the Inner Sphere. It remained in wide use through the Jihad, but by the Dark Ages it had fallen out of use except amongst less fortunate mercenaries and the Periphery.

Read This First

  • Your LRMs and large laser work well at range against light targets or to soften up heavy targets
  • Once a target is closer than 6 hexes, look for a secondary target for your LRM while firing everything else at your main target
  • You have plenty of ammo and run cool, so fire at will
  • Your left torso has a high chance to explode and will leave you with only the large laser still functional

Thunderbolt TDR-7M

  • Role: Brawler
  • Tech Base: Inner Sphere (3049)
  • Chassis: 65 tons
  • Movement: 4 / 6
  • Armor: 206 (Ferro Fibrous)
  • Heat Sinks: 15 (30)
  • Weapons:
    • ER Large Laser
    • LRM 15 (ammo: 16)
    • Medium Laser × 3
    • Streak SRM 2 (ammo: 50)
    • Machine Gun × 2 (ammo: 200)
  • Equipment:
    • CASE
  • Design Quirks:
    • Multi-Trac
    • Rugged (2)
    • Ubiquitous
  • Cost: 6,093,560 C-Bills
  • Battle Value: 1,495


The TDR-7M has fairly average mobility for a heavy ’Mech. It can walk 4 hexes for a +1 target movement modifier or run up to 6 hexes for a +2 target movement modifier. It is not equipped with any jump jets.


Like the TDR-5S it was based on, the Thunderbolt TDR-7M is well-armored and durable. It carries about 98% of the maximum amount of armor and then has CASE to protect it from ammo explosions. The left torso is more vulnerable to those explosions with 30% of its slots exploding while the right torso has only a 10% chance of a critical slot being explosive ammo. It still uses a standard engine, so losing a side torso doesn’t result in any engine damage. Losing a side torso to an explosion does take out a lot of its firepower though, especially because the engineers designing it stored the missile ammo on the opposite side of the torso from each launcher meaning that losing either side means that a MechWarrior can no longer fire either SRMs or LRMs.


The TDR-7M’s armament is based on the TDR-5S with a couple of upgrades. The large laser is replaced with an ER large laser and the short-range missiles are replaced with a Streak launcher.

At long ranges, a MechWarrior can use the LRM launcher and ER large laser. Those have respective ranges of 21 and 19 hexes, and can cause up to 23 damage. Inside ranges of 9 hexes, the medium lasers and Streak launched nearly double that potential damage. The machine guns offer an efficient option against conventional infantry at short ranges.

Maximum and Expected Damage

The TDR-7M has an unusual range profile for its damage output. The LRM loses accuracy within 7 hexes, but that loss in expected damage is offset by the short range weapons. That means there is a relative peak for damage output at 6 hexes and then a jump back up inside of 3 hexes. When inside of the minimum range of the LRMs, a MechWarrior can make good use of the Multi-Trac quirk in order to fire the LRMs at a secondary target in a more accurate range band while using the rest of their weapons to fire at their main target.

Maximum Damage for Firing Arcs

The TDR-7M has a good number of weapons that depend on ammunition, but it carries enough shots that it should not be a problem during most engagements. The most likely weapon to run out of ammo is the LRM launcher, but even that can be fired 16 times before that happens.

Heat Management

Thanks to its upgrade to double heat sinks, the TDR-7M won’t overheat during normal use. It can build up 28 heat with its weapons plus 2 more while running, and then its cooling system can dissipate all 30 of those heat points. That means a MechWarrior should only need to hold back fire to manage heat levels in extremely hot environments or after taking damage to their engine shielding or heat sinks.

Heat-Adjusted Maximum and Expected Damage


As a complement to its short-range firepower, the TDR-7M is fairly capable in a brawl. Both of its arms have full actuator sets that allow for solid 7 damage punches. The right arm needs to give up the potential 8 damage from its large laser to punch though, so shooting is generally a better option unless a MechWarrior really wants to focus on damaging a target’s upper body. The Thunderbolt can also kick for 13 damage.

Cost & Upkeep

Thanks to its focused upgrades, the Thunderbolt TDR-7M is only marginally more expensive than older models. The Streak missiles are more expensive per ton, but also more efficient in their usage. In Chaos Campaign, the TDR-7M is at a disadvantage since it ends up paying the increased price for its technology even though it has a relatively small amount of upgraded tech.

When using the Warchest Point system, these are the expected costs for the Thunderbolt TDR-5S:

Purchase1,300 SP
Armor Repair65 SP
Structure Repair130 SP
Reload5-25 SP


The plastic Thunderbolt included in the A Game of Armored Combat box works well to represent the TDR-7M. Iron Wind Metals also offers a metal version of the same sculpt.


More ’Mech Manuals

By Scott Boehmer

A game enthusiast and software engineer.

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