Introduction

Towards the end of the Second World War, the Soviets commissioned the construction of a prototype heavy self-propelled gun as a possible replacement for the ISU-152.

The Object 704, (or ISU-152 mod. 1945 as it was also called) was based on the brand new IS-3 design (but using some components from the IS-2) and, unlike the ISU-152 it was to replace, carried thick sloping armour (120mm at an angle of 50 degrees on the front plate). The height was reduced from the ISU-152 making the working conditions inside the vehicle more cramped. This was slightly compensated for by making the vehicle slightly wider than the IS-2/3 series they were based on.

The main weapon was an updated version of the ML-20 used in the ISU-152, the ML-20SM mod 1944. Unlike the earlier version this had no muzzle brake.

The tank successfully completed all trials, although complaints were raised about crew conditions within the more crowded fighting compartment, but in the end the biggest problem that it faced was that the standard ISU-152 was more than good enough. The ISU-152 remained in front-line use with the Soviet armed forces for decades more, being officially retired in 1972 (although some remained for secondary uses). The last known combat use of the ISU-152 was in 1991 in Iraqi service during the Gulf War.

The prototype of Object 704 survived and now resides in the collection of the Kubinka Tank Museum just outside of Moscow.

The Kit

For anyone interested in modelling this impressive vehicle in 1:72 scale, OKB Grigorov have produced a phenomenal replica in this scale. The kit contains 83 resin and 9 metal etch parts.

Those who have not come across OKB Grigorov’s kits before and who may be used to more traditional ‘cottage industry’ resin kits will be in for a very pleasant surprise. The detail is nothing short of astonishing. The kit is computer-designed and mastered on high-end industrial 3D printers (it’s impossible to see any evidence of layers, even under magnification). Take a look at the close-ups of the IS wheels, far more detailed than any available in plastic kits (these, and the tracks, are available separately for those wanting to upgrade those kits).

The hull is in two hollow parts, which dry-fit together flawlessly. The suspension is highly detailed with separate suspension arms, wheels in two parts and resin tracks in two long lengths for each side. When gently warmed these wrap around the wheels effortlessly, and there is plenty extra length provided to ensure the most generous of sag if required (although period photos show the tracks fitted with only a small amount of sag).

It’s obvious from a simple Google search to research the Object 704 that one of the main reasons for the popularity of this obscure 1945 prototype is its appearance as a Tier 9 Russian Tank Destroyer in the game ‘World of Tanks’. OKB Grigorov are capitalizing on this popularity by including, along with the standard barrel, a second barrel for the long BL-10 high-velocity 152mm gun that is an optional add-on to the tank in ‘World of Tanks’.

This gun was never fitted to the Object 704 in real life, but that hasn’t stopped OKB Grigorov from including it, and that turns out to be a very good thing, as I will explain a little later.

The kit comes well-packaged and boxed, with instructions but no decals as none are needed for the prototype, and for those doing a ‘what-if’ service version, items from your spares box will no doubt suffice. The instructions don’t mention the second gun option, and they also don’t mention two long strips of resin, but these are to fit on the underside of the upper hull to hide the hollow area immediately above the tracks.

Conclusion

It’s difficult to come up with any serious complaints about this kit because it is just so well made, however the biggest drawback for many will be that none of the hatches can be opened. Not only are they moulded shut, but the resin on the roof part is so thick it would be a major operation to try to open any of them up. No DShK AA gun is included in the kit either, despite it being prominent in all photos of the prototype under test, and similarly the prototype carries a pickaxe prominently on the left hand side which is missing from the kit. Neither of these items would prove a challenge to any competent modeler with a spares box however.

I do not think anyone currently producing 1:72 resin armour kits comes close to OKB Grigorov in terms of product quality - but then this is reflected in the price. Ukrainian producer Armory Models have announced a resin conversion for the Roden IS-3 kit, but the suspension in that kit is not particularly good, and it uses vinyl tracks - the Trumpeter IS-3 would have been a much better starting point.

I highly recommend this kit. I purchased it directly from the manufacturer on their website http://www.okbgrigorov.com. I have no connection with OKB Grigorov other than being a happy customer.

The BL-10 gun, as impressive as it is on the Object 704, was never fitted to it in reality. However, this gun was tested on the ISU-152-2 - another soviet one-off prototype. It turns out that building this is very easy using the BL-10 gun in this kit and an Italeri 1:72 ISU-152 kit. The gun simply replaces the kit gun - in the same mantlet - and you have two obscure Soviet SPG prototypes for the price of one (plus an Italeri kit). In addition, the ISU-152-2 was not seen with the DShK AA gun, which is provided in the Italeri kit, so that can go on to the Object 704!