Historical background

The Object 704 or ISU-152 ver. 1945 or Kirovetz-2 was an experimental Soviet heavy self-propelled howitzer developed at the end of the Second World War. It was developed by the team of Yosef Kotin who previously lead the development of SU-152, ISU-152 and ISU-122. Object 704 was based on newly produced IS-3 tank hull which had radical design and improved armour thickness when compared to IS-2 tanks. Same idea was driving the development of Object 704 – improve protection of self-propelled artillery. This was achieved by both improved thickness and sharper angles for armoured plates. Overall, Object 704 was the most protected mobile artillery piece at the end of WW2 capable of resisting the fire from an 88mm Pak43! Simultaneously it weighted only 1.3 tons more than ISU-152 thanks to reorganized fighting compartment. Here the design bureau decided to test a modification of ML-20 howitzer – ML-20SM which had no muzzle brake. That automatically increased recoil and reduced the space in the fighting compartment. ML-20SM could provide direct fire up to 1000m and indirect up to 13 km. Additionally there was 1 coaxial DShK MG controlled by commander and 1 anti-aircraft DShK MG on the roof of the fighting compartment. Crewed by 5 men it had 3 members on the left side (driver, gunner and loader), plus 2 on the right (commander and assistant loader).

Although involving some interesting design ideas and carrying powerful armament the field tests revealed that the crew lacks comfort and especially the driver was getting tired too soon. This project never went further than the only test prototype (exhibited nowadays at Kubinka museum).

Based on IS-3 hull one would expect that Object 704 could have been released by Trumpeter years ago, but it was only available as rare resin conversion. Unlike the German WW2 paper panzers (that never existed in flesh!) there was little interest in rare Soviet vehicles among styrene manufacturers. However, being one of the most powerful AT guns in the famous World of Tanks game these giants got another chance. Some time ago Trumpeter announced IS-4, Object 704, IS-7 (the first 2 are already on sale now) and I assume there will be more Soviet heavy machinery coming from that manufacturer. Trumpeter is known for producing new kits in good tempo but how accurate are these when it comes to scale realism? We’ve read a lot of critique and a lot of praise and it was interesting to me (apart from the subject being attractive by itself) to see what changed during the last 4 years (I had only 2 Trumpeter kits during that time).

Kit review

Following a great teaser video and thorough sprue images already published on Armorama, a link to which can be found at the end of this review. I would like to show you how the kit actually builds and provide observations on accuracy and the replication of the original vehicle.

The original images of Object 704 are scarce but you can find some from the field test on the web and in a Russian-language publication regarding IS-3 tank. The real vehicle standing at Kubinka is covered on WoT related webpages and also on Facebook of Wilder, however I noticed several features that are not present on the original images from 1945. For information, there are no hatches on the rear side stowage boxes (these are simply welded shut with metal sheet) and, most noticeably, the tracks on the museum vehicle are a mix of several different types, including track links from IS-4 (or T-10 heavy tanks). Therefore I strongly recommend to those who would like to build a replica of real vehicle from 1945 to refer to 4-5 old black and white images available online.

A first impression I got from the kit upon opening the large cardboard box was that it looks very nice on the sprues and the moulding quality is nice. Without wasting any time I started building it and the very first step confirmed my initial thoughts.

The large road wheels have good cast steel detail with reinforcing ribs on both sides. These are made of 2 halves plus one hub cap. Here it is important to polish the working surface of the road wheels to remove mold seam line. The sprockets are again of 3 parts – 2 halves and 1 cap. Interestingly, the outer sprocket part has very nice bolt detail that will be covered by the cap but it can be a good starting point if you decide to have the cap off (although you will have to make holes for the cap bolts and remove existing cup location points). Most impressive is the detail on the slotted hex nuts on the inner surface of the drive sprocket halves. Finally, there are 6 steel rollers also made of 3 parts. No problem with assembly at this step and again the working surface of the rollers should be polished a bit with a file.

Next we add suspension parts to the hull and it should be noted that lower hull part has very good weld detail on the bottom which is something that nobody would see, but nice to have on the model anyways. Care should be taken with parts C2 and C11 as they should be on the appropriate hull sides as they serve for proper position of the torsion bars. Amortization parts C9 are rather difficult to clean up as they have molding seam exactly on the bolt head with a washer. Possibly you could replace these with aftermarket bolts if desired. The road wheel hubs (A1 and D9) are easily positioned on their location points, however 3 or 4 of these had a loose fit and I advise inserting all of the parts that have firm fit first, glue them and then insert those that have loose fit so that in the end all bars are touching the bench meaning that the wheels will do so as well. The idler tension mechanism does not allow any repositioning here but I am sure those who would like to do that would be able to modify parts.

Overall, the running gear looks like the running gear of Object 704 and it seems to me from the images available online, that Trumpeter updated their tooling from IS-3 kits here (correct me if I am wrong).

When reaching the tracks I discovered a significant problem – the individual tracks included in the kit are almost 2mm wider then they should be (this issue is common for KV-1S tracks from Trumpeter). Object 704 used the same type of tracks as KV-1S, IS-2 and IS-3 and these were 650mm lightweight tracks. So if you care about accuracy you should replace the plastic tracks with aftermarket offering, for example Masterclub metal tracks (as I did).

With the chassis complete the build continues with adding the large superstructure undersides to the lower hull. These have location points on the hull which should be filled with putty afterwards. Moreover, on a real vehicle there are weld seams where the superstructure joins the lower hull, a feature absent in the kit. Most likely these areas would be covered by mud and dirt on a finished model, but keep that in mind!

Before gluing the upper hull part with superstructure it is important to glue the photo-etched mesh from the inside as well as loaders periscope. I wish Trumpeter did some kind of imitation of the engine room so that when you glue the upper hull part you do not see the bottom of the hull.

On the rear end of the lower hull there are 2 towing hooks with locks and 2 spare tracks. The towing hooks look similar to those on the real vehicle however the locks would be too close if you glue them as per the instructions. I sanded off the location marks and glued these a couple of mm closer to the bottom referring to the walk around images.

The rear hull deck has appropriate detail with bolts and 2 access hatches with ring-formed handles. The noticeable difference with the real vehicle is the presence of rear (smoke?) drums which were never placed on the real vehicle but have been added by WoT designers in the game. The smoke drums have OK detail, which is rather simplified comparing to real mechanism and also as this was not a feature of the real vehicle I omitted installing them. Other details present on the rear of the hull are large handle for opening of the rear access door, rear lights and small parts like hooks for attachment of the towing cable. Unfortunately there is no cable included in the kit and no tow shackles which are clearly seen on the 1945 images. Small PE parts are given to replicate the loops on the rear wall of the superstructure but no straps for the tarp are present (these can be made of foil, PE leftovers or taken from newly available PE set for Object 704 from E.T. model). The external fuel drums are very nicely detailed and capture the real example quite accurate.

The roof of the superstructure has good detail, however there is an issue with the drivers and commanders hatches. Trumpeter supplied them as a single circular part with a periscope, while on the real example the section with periscope is independent from the hatch while being in the same rotating ring. The hatch itself opens by sliding it to the side, similar to hatches on King Tiger or Panther. While this is not a problem if you would like to depict a model with closed hatches, if you would like to do so you would have to do some surgery (please refer to video published on WoT youtube channel, where you can actually see how the hatches are opened). That leaves only 2 options for opening the hatches – loaders hatches in the rear of the superstructure (D12). These have torsions coming (D6), and some trimming is necessary if you would like to have the hatch open. Also no detail is present on the inner surface of these loaders hatches, so one has to watch the videos on youtube to understand what was present there. The hatch in the middle was not for the gunner to enter the vehicle but for the installation of the panoramic gun sight when opened.

Other details on the roof include DShK 12.7mm anti-aircraft machine gun with a stand which has quite good detail, apart from the barrel opening and muzzle brake molded shut. A solution would be a turned metal barrel from RB model or resin from Tank or MiniArm.

The main armament assembly is straightforward. Gun tube is glued into inner mantlet parts that are glued into the hull. Here I discovered that it is better to glue part G29 to the superstructure first and then glue G16 and other elements from step 12 to it. This will ease the alignment; however I ended up filling the seam and imitation of cast steel texture with putty to hide the seam. Next the mantlet cover is attached to the movable gun tube and cap closes the area between mantlet and mantlet cover from top. For the barrel Trumpeter has provided a turned metal option together with plastic two-piece barrel with PE insert to replicate the rifling. Both actually do not represent the real Object 704 barrel as the shape of the tip is a bit more complex and the metal barrel included has no rifling, while plastic has it out of scale. As I am writing this RB model already released a proper shaped barrel which I plan to install on my model (you can follow the build log here on Armorama, a link to which is at the end of this review.

As this was a test vehicle there is not much you can do with painting; plain 4BO and not that bright green tone shown on the boxart. Otherwise the painting is only limited by imagination if one depicts a hypothetical vehicle during the early days of the Cold War or examples from WoT. Trumpeter provided some digits and guards insignia as decals.

Conclusion

I think this is a very interesting model to build, without fit problems and not over engineered. The detail level is reasonable for an out of the box build, however, there is a range of issues that do not make the kit perfect and good replica of the original self-propelled howitzer. These include incorrect tracks, incorrect barrel tip shape and impossible to open the driver’s or commander’s hatch. Correction and improvement will add costs to not a very cheap kit, so the degree of scale realism is up to modellers budget and demands. If you just want to have something that resembles your favorite vehicle from the WoT game – you can build it out of the box without any alterations.

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