HGUniversal Century

RX-78-6 Gundam G06 (Mudrock)

The heavy-hitting Guncannon cousin nobody asked for, and the one that turned out to be a genuine HG sleeper.

MechaGrade Score

4.1/5

Gundam G06 (Mudrock) · 1/144 · 2019

GradeHG

Scale1/144

Released2019

Runnersn/a

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The verdict

I went into this expecting a reskinned RX-78-2 with a bigger backpack and came out surprised at how much engineering Bandai actually packed into it.

The 360-degree forearm twist alone makes this one of the more expressive HGs I have posed in this scale. It is a P-Bandai exclusive so you will pay a premium and hunt a secondary market to get one, but the kit itself earns the asking price.

Best for: UC completionists and HG builders who want a genuinely new engineering trick, not just another RX-78 repaint

The full review

What it is

Mudrock is an M-MSV what-if suit, an RX-78 prototype pushed toward sustained firepower instead of RX-78-2's one-good-beam-rifle-and-hope approach. The kit backs that lore up with hardware: dual 300mm cannons on an enlarged backpack, arm-mounted grenade launchers, and a chest and shoulder silhouette that reads more Guncannon than Gundam. Bandai molded all 11 runners fresh for this release, no recycled RX-78-2 sprues, and it shows in how deliberate the proportions feel. Building it, the suit does not feel like a variant slapped together from spare parts. It feels considered.

The catch

This is a Bandai Premium (P-Bandai) exclusive, so you are buying secondary market or import, and pricing runs well above a standard HGUC at retail. A handful of parts, mainly the backpack thrusters and lower leg trim, need paint to actually match their intended color since the kit does not lean on stickers for separation the way most HGs do, which is a plus for looks but a small ask if you build strictly out of the box. The suit's oversized backpack and cannon assembly also add some rear heaviness that affects how confidently it stands in a deep back-lean pose.

Who it's for

Get this if you already have an RX-78-2 on the shelf and want a suit that actually differentiates itself mechanically, not just in color. The swappable shoulder and calf armor, letting you build Mudrock in its stripped-down or full-loadout state, is a legitimately fun modeling choice for someone who likes options over a static build. Skip it if you are new to the hobby and price-sensitive, since a standard HGUC RX-78-2 gets you a similar era and grade experience for less money and less hunting. This one is for builders chasing the deep cuts of UC's mobile suit design history.

The build story

What the build is actually like, and the engineering worth knowing about.

The build itself runs like a well-behaved HG: nub placement stays mostly on non-visible surfaces, joints snap together with confidence, and nothing about assembly fights you. Where it earns its keep is the frame underneath the arms. The double-jointed elbow paired with a purpose-molded polycap lets the forearm spin through a full rotation, something HGs at this price point almost never attempt, and it changes how natural gun-holding and dual-wielding poses look on the shelf.

Color separation is handled almost entirely through molded plastic rather than stickers, which is unusual for the grade and pays off in how clean the suit looks unweathered. The dual 300mm cannon backpack and arm-mounted grenade launchers give it a distinct silhouette from any RX-78-2 variant, and the swap-in shoulder and calf armor pieces mean you effectively get two builds worth of display options out of one box.

Lore & trivia

01Mudrock was designed within Kunio Okawara's M-MSV (Mobile Suit Variations) original line as a what-if answer to the RX-78-2's biggest flaw, running out of beam rifle energy with no backup firepower.
02Its design was later reworked for the game Mobile Suit Gundam: Zeonic Front by artist Keiichiro Katagiri, which is the version this HGUC kit is based on.
03The suit's twin 300mm low-recoil cannons take direct visual and mechanical inspiration from the RX-77-2 Guncannon, tying its design lineage to two different RX-78 offshoots at once.
04This HGUC release was the first RX-78-type HG to introduce the triple-axis forearm articulation gimmick, a feature Bandai later reused across several subsequent HGUC kits.