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Hobby Boss 1/72 Kits

Moerser Karl-Geraet 040/041 Initial Version

Moerser Karl-Geraet 040/041 Late Version

Hobby Boss announced two 1/72 Karl kits (kit #82904 and #82905) at the Sizuoka Hobby Show in May 2007. Although both kits were initially scheduled to be released in Summer 2007, only the kit #82904 came out in late August, followed by the kit #82905 in December.

Hobby Boss's band new kits are very welcome, as Hasegawa kits have been the only game in town in 1/72 world since their first appearance in 1970s, and they have some major research issues (as discussed in this page), even after Hasegawa refurbished their kits in 2006.

I don't know what Hobby Boss thinks are the best features in these kits. But, if I were to write a small note to accompany the kits displayed at a hobby show, I would list:

  • Both 60cm and 54cm barrels are included.
  • Reproduces Karl Nr.I and Nr.II with 8-wheel chassis (#82904).
  • Reproduces Karl Nr.III through VI with 11-wheel chassis (#82905).
  • The barrel recoils by coil spring parts.
  • Accurate details based on the most recent research studies.

▼Kit Contents▼

Both kits consist of about 190 parts each shown in the table below.

#82904 Initial Version #82905 Late Version
Chassis 8-wheel chassis 11-wheel chassis
Running gear Sprues A, B Sprue G
Upper structure and details Sprues C, D
Gun barrels and cradle parts Sprues E, F
Tracks Vinyl track
(Early type, 170mm pitch)
Vinyl track
(Late type, 240mm pitch)
Metal parts One shaft and four coil springs
Decals For Karl Nr.I and II For Karl Nr.III through VI

Details are rich and well defined. I suspect Hobby Boss studied Trumpeter's 1/35 kit very well, and designed the kit accordingly. In fact, similarity is striking, although individual parts design and their assembly are not exactly the same.

I see flash and ejector-pin marks on some parts. There also are some parts with rough surface, because its mold was not polished enough.

Barrel and Cradle

Both kits can be built as Geraet 040 with 60cm gun, or Geraet 041 with 54cm gun. Barrels and loading trays for both types are appropriately provided. The counter weight(?) on the breech block of the 54cm gun is also included.

There is one part missing for the 54cm barrel. See the right photo. There should be a thin ring at the front of the collar of the barrel. In the photo, I made a ring (outer diameter: 12.5mm, inner diameter: 9.5mm) out of a 0.3mm plastic card. The 60cm barrel does not require this ring.

Parts for 60cm and 54cm barrels

Missing "ring" for the 54cm barrel
The gun cradle is very well reproduced; many rivets and small details are finely molded, although there are some omitted rivets, which you may want to add. Unfortunately I found some sink marks on some parts. These are difficult to fill, because there are many small details and rivets molded around there.

The recuperator housing was made of cast metal in the real vehicle. Thus, you may want to add some rough texture to the area shaded with pink in the right photos. Note that part of the front and back end of the housing was machined to smooth surface, and you should not add texture there.

There is a distinctive horizontal bar above the gun collar on the front face of the recuperator housing of Karl. This is somewhat missing in the kit. To me, this "eyebrow" of the gun is a characteristic feature of Karl, and would like it to be reproduced!

For an unknown reason, Hobby Boss decided to provide no ammunition in the kit! It is most puzzling, and I would hope that resin or metal ammunition will be sold by third parties.

The breech block is molded shut, thus, it is necessary for you to do a bit of surgery, if you want to build a diorama where Karl is being reloaded.

Cast texture

Running Gear

#82904 Initial Version #82905 Late Version

The kit #82904 represents the 8-wheel chassis, which corresponds to Karl Nr.I and Nr.II. The other kit #82905 has the 11-wheel chassis for Karl Nr.III through VI. In both kits, suspension arms are molded fixed to the chassis part, thus, the kit reproduces the "Automotive" mode of Karl, and you cannot model the "Firing" or "Railway Transport" modes out of the kit. I wish Hobby Boss designed the kits so that they can be built either the "Automotive" or "Firing" modes.

Tracks are made of vinyl, and are glueable with CA glue. "Initial" Karl and "Late" Karl used different track links, and the two kits reproduce this subtle difference correctly. Width and pitch of the track link look dimensionally Ok. The length is, as shown in the photos, neither too long, nor too short; just adequate. Note that the tracks of Karl did not appear to have much sag in the "Automotive" mode.

If I become a bit picky, I would point out that upper return rollers in #82904 are slightly too large. On the real vehicle, the diameter of the upper return roller was about 280mm, that is about 3.8mm in 1/72. The diameter of the kit part is about 4.7mm. Interestingly, the upper return roller in Trumpeter's 1/35 8-wheel chassis kit is also bit too large :-)

It appears that some #82905 Late Version kits contain early type vinyl tracks (for #82904), rather than the correct, late type tracks. Examine the vinyl track sprue, and verify that it has the correct part number (see photos below).

#82904 Initial Version tracks #82905 Late Version tracks


Eight connection points, with which Karl is mounted on purpose-built transport railcars, around the upper structure are well produced using the slide mold. Big bolts are finely molded too. However, shafts which connect Karl to railcar crane arms are somewhat missing.

OVM tools are molded on the rear end of the vehicle.

Rear end
The driver's compartment is well reproduced, including small levers. The instrument panel has slightly vague mold as compared with other details in the kit. The cover (D21) for the driver's compartment is also provided. However, this cover is apparently not used when Karl is in the "Automotive" mode as depicted in the kit.

The round grill (D27) is rather thick and unimpressive. We may be able to use some parts in Eduard's PE set for Hasegawa kits to enhance this and other bits in the kit.

Four walk (or work?) decks along the upper structure are molded fixed to the upper structure, and cannot be built as "folded" without a bit of surgery. (Because of that, I suspect Hobby Boss does NOT have a plan to release another Karl kit with railway transport.) There are a number of ejector-pin marks at the back of these decks and fenders. While these will not be easily visible when assembled, they will not be completely covered either.

Front end and driver's compartment


The sheet of decals for Karl Nr.I "Adam" and Nr.II "Eva" is included in #82904. Note that, to the best of my knowledge, there aren't any war-time photos showing Karl Nr.I and Nr.II sporting these nicknames painted on the gun. The reference [38] does mention that the name "Adam" was discovered on the vehicle preserved in Kubinka, when the paint was peeled, though.

Decals in #82905 are for Karl Nr.IV "Thor", Nr.V "Loki", Nr.VI "Ziu", and Nr.III. The name "Odin" for Nr.III is NOT included in the decal sheet. As there has not been a single photo showing the name "Odin" painted on Karl, I found this omission acceptable.

Decals: #82904 Initial Version Decals: #82905 Late Version

The instruction booklet is very well presented, and is not crammed and busy as in some other manufacturer's. There is a separate color painting and decal guide as well. However, the painting guide in both kits shows Karl in rather uninteresting Panzer Gray only! It would have been better, at least in #82905 Late Version kit, if it had had 3-tone camo scheme for "Thor", "Loki", and "Ziu" as seen in Summer 1944.

The box art does NOT exactly correspond to the kit parts, in the sense that both kits represent Karl in its "Automotive" mode in which suspension is in active, running configuration, whereas the box art depicts Karl in the "Firing" mode in which the suspension is inactive. (Such discrepancy exists in other Karl kits as well.) If one knows enough or has good reference about Karl, he realises the kit correctly represents the "Automotive" mode. But, if one doesn't know much about Karl, he may be surprised when he finds the assembled kit look somewhat different from the box art.

▼Tips for Detail Up▼

  1. Added cast texture.
  2. The "eyebrow" above the gun collar is added.
  3. Re-did wiring (piping?) on the gun collar. The mold in the kit is somewhat strange. There should be two wires (pipes?) on the upper side of the gun collar, and three wires on the lower side.
  4. Added four rectangular blocks (stoppers?). IFAIK, there is no kit which reproduces these blocks yet.

  1. Added missing rivets.
  2. Replaced molded-on handles with plastic rods.
  3. Replaced molded-on handles with a thin wire.
  4. Used a piece from Eduard PE set 22059.

  1. Replaced molded-on handles with a thin wire.
  2. Replaced molded-on handles with plastic rods.
  3. Round top of the ladder is recreated.
  4. Used Eduard PE set 22059 for the round grill and Notek light guards.
  5. Missing shafts (1.1mm) are added.

▼Comparison with Hasegawa 1/72▼

Hobby Boss #82904 "Moerser Karl-Geraet 040/041 Initial Version" kit is in the middle. It is partially painted, and some parts are not glued or attached, because of my painting plan. The right is Hasegawa's revised kit (MT56) mostly out of the box. This kit is meant to be 54cm barrel Karl (Geraet 041) with 11-wheel chassis. But, I built it in the same configuration as Hobby Boss kit, 60cm barrel and 8-wheel chassis, as the kit also has these parts as unused spare parts. The left is old Hasegawa kit substantially corrected and detailed.

Dimensionally Hobby Boss and Hasegawa kits are similar to each other. Hasegawa kit seems only slightly taller, and its recuperator housing is wider than Hobby Boss's. This makes Hasegawa kit look somewhat muscular. Accuracy and details are obviously better in Hobby Boss kit; it is rather harsh for 30 years old Hasegawa kit to be equal to the most recent kit.

▼Notes on the Instruction Sheet▼

Unless otherwise stated, the following notes apply to both #82904 Initial Version and #82905 Late Version kits.

  1. Step 1
    #82904: Enlarge the hole in the road wheel part B2 slightly (about 1.6mm), so that it will fit the suspension parts A1 and A2 easily.

  2. Step 3
    Dry fit D10, D11, and F30 carefully.

  3. Step 4
    There is a typo in the instruction regarding exhaust muffler parts.
    Correct pairs: D25 and D29, D12 and D14
    Wrong pairs in the instruction: D25 and D14, D12 and D29

    There are some ejector-pin marks on the back of upper hull side parts C4 and C5. Remove them thoroughly, otherwise you will have gaps between upper hull C2 and them.

  4. Step 5
    Extended exhaust pipes (D6 and D26) are not always fitted to Karl. If you want to reproduce a particular vehicle in particular time-frame, you had better consult your reference.

    D21 is the cover for the driver's compartment. It is supposed to be unnecessary for Karl in the "Automotive" mode as depicted in the kit.

  5. Step 7
    When you put front and rear panels (F18 and F23) to the hull, you will probably have small gaps around them.

  6. Step 8
    Recuperator assembly of the kit has a gimmick to recoil the barrel, using 4 coil springs. If you follow the instruction, you had better plan how to avoid 4 rod parts (F3) falling inside the recuperator housing. (Hasegawa kit has better assembly in this regard.)

    Assembly in Hobby Boss kit

    Assembly in Hasegawa kit (MT56)

  7. Step 9
    Fit between F21, F29 and the 54cm barrel (E1 and E10) is too tight. You had better enlarge the holes in F21 and F29. 60 cm barrel parts do not have this problem.

    There are some sink marks in the breech block part F31.

  8. Step 10
    Be careful when putting cradle parts together, otherwise you will have gaps and the distorted cradle. F9 is a boresight and I assume it is not fitted there when Karl was in the "Automotive" mode as depicted in the kit.

  9. Step 11
    The loading tray has different shapes for 60cm and 54cm barrels. Do not confuse their parts. The position of the upper tray parts (E5 and E9) is not very clearly indicated in the instruction. But, this upper tray part "slide" against the lower part (E17 and E19), and you do not need to worry too much.

  10. Step 12
    Dry fit F25 and F26 well, as their fit is not good.


I found these Hobby Boss kits very well done. They are superior to 30-years old Hasegawa kits in every aspect, and the best 1/72 Karl kits without any doubt. I would also like to see Hobby Boss (or Trumpeter) will release Munitionsschlepper auf Panzer IV fuer Karlgeraet in 1/72 in the near future, as Hasegawa's kit looks too crude when placed alongside of these new kits.

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Hobby Boss

Karl-Geraet, Kits and Information
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Created: Sunday September 30, 2007
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