#6047 JSU-122S/152 Tank Destroyer

This kit gives you the option to build an ISU-152 armed with the 152.2mm ML-20S howitzer or an ISU-122S armed with the 122mm D-25S gun.  The ISU-122S was distinguishable from the ISU-122 by the prominent TsAKB muzzle brake; the weapon was very similar to the D-25T carried by the IS-2 and IS-3, whereas the ISU-122 carried the 122mm A-19 gun which lacked a muzzle brake.

The kit uses most of the components from DML's kit #6803 Chinese JSU-152 Howitzer.  In fact the box contains that kit in its entirety, along with the instructions and decal sheet, so don't panic when you open the box and see the instruction sheet for kit #6803.  This kit adds an additional supplemental instruction sheet and a small decal sheet with an additional marking option for an ISU-122S.

Step 1 of the kit instructions direct you to assemble the sprockets, road wheels/idlers (the road wheels and idlers were identical on the IS series) and return rollers.  As noted in General Comments, the road wheels are slightly undersized and you can replace them if you wish.  The kit return rollers represent the later pattern with three large lightening holes, which were introduced in June 1944 and are therefore appropriate for an ISU-122S or for an ISU-152 from that time onward.  If you wish to backdate your model to represent an ISU-152 from late 1943 or early 1944, you must fill the lightening holes.  John Stevens has come up with a way to do this which is described here.

Step 2 of the kit instructions deals with the lower hull.  As with all the DML IS series kits, the lower hull is too low and requires raising as described in General Comments.  The kit correctly includes the ammunition loading port (part B32) in the left-hand side of the lower hull.

The kit instructions give you the option to remove the mounting plates for the spare track links on the lower front hull.  Track links were fitted commencing in May/June 1944, and retro-fitted to many earlier vehicles so check your references for the vehicle you are modeling.  If you wish to model a late 1943 or early 1944 ISU-152 as built, remove the mounting plates.

Complete Step 3 of the kit instructions, adjusting the position of the lower rear hull plate (part A8) to meet the rear edge of the upper hull due to the modified lower hull tub.

The tracks included in the kit are the single link type with a guide tooth on every link, which were introduced in the spring of 1944 and became common in the summer.  They are therefore appropriate for all ISU-122Ss and for ISU-152s from that time onward, though most photographs of post-war vehicles show the later tracks with holes in the sides of the guide teeth.  These are represented by Modelkasten's set SK-9. Note that the earlier split-link tracks persisted in service until the end of the war however, so check your references for the vehicle you are modeling.  You can substitute split-link tracks from the Cyber-Hobby IS-1/IS-2 2-in-1 kit #9108, ISU-152 3-in-1 kit #9112 or after-market sets including Friulmodel set ATL-54, Masterclub 135023W and MiniArm sets B35002 or B35017.

The instructions tell you to cut out the locating points for the spare track links on the front edge of the glacis in Step 7.  However, all the detail parts will then be in place on the upper hull and you risk damaging them during the cutting process.  I recommend cutting out the locating points at the beginning of Step 4.  You should do this if you are modeling a vehicle from the period after May/June 1944 since, as noted above, the track links were fitted to all new production vehicles after that time, and retro-fitted to most earlier vehicles.

The engine air intake screens and the radiator exhaust air grille on the engine deck are molded integrally with the hull top.  The mesh on the air intake screens is quite well represented and the frames include the attachment bolts, but you may wish to cut them out and replace them with etched brass screens.  Limitations in molding technology of the time mean that the kit does not properly represent the undercuts beneath the louvres on the radiator exhaust grille, but this is not easily noticeable on the finished model.

The towing shackle stowage bracket on the front left-hand fender is rather poorly represented and should be replaced with a suitable part from an after-market set.

The mounting bracket for the spare hydraulic fluid container (part D16) is mounted in the correct position for a vehicle from mid-1944 onward.  However, if you are modeling an ISU-152 from late 1943 or early 1944 and are omitting the spare track links, you should relocate part D16 to the lower front hull between the towing hooks.

The forward pair of handrails on the forward superstructure side plates were only fitted to post-war vehicles, so check your references for the vehicle you are modeling.

The lifting eyes (parts B20) are molded with the rings standing perpendicular to the plates on which they are mounted.  The rings were free to swivel in their mounts and typically laid flat against the plates.  The kit parts can be modified by carefully cutting the rings from the eyes and re-attaching them in a more natural position.  This applies not only to the superstructure and engine deck lifting eyes but to those on the rear hull (Step 6) as well.

The external fuel tanks (parts B15, B16, B17, B18 an B19) represent the 100-litre type common during the Great Patriotic War, rather than the larger-diameter 160-litre type commonly seen on post-war vehicles.

Step 5 deals with the 152mm gun and mantlet.  The gun barrel is molded in two halves with the muzzle brake molded integrally with the barrel.  The kit parts will respond well to careful assembly and cleaning up, but you may wish to replace them with an after-market barrel.

If you wish to complete your model as an ISU-122S, ignore Step 5 of the main instruction sheet and instead complete Steps 1, 2 and 3 of the supplementary sheet.  These step assembles the gun, mantlet and gun mount.  The 122m D-25S gun barrel is molded in two halves, with the muzzle brake halves molded integrally with each half of the barrel.  You may wish to replace the kit barrel with an aftermarket item; the barrels from the D-25S and D-25T were identical.

The ISU-122S mantlet lacks the grab handle on its left-hand edge.  This can be added from thin wire.

In Step 6, note that the panel lines around the maintenance and inspection hatches on the upper rear hull plate (partA1) are extremely faint and would benefit from rescribing.  If you do not do this, you risk accidentally obscuring the lines when you paint your model.  The kit also lacks the rain gutter above the maintenance hatch, which was fitted to all vehicles from the late spring of 1944 onward, and retro-fitted to most earlier vehicles.  This can be easily added from thin styrene strip.

Strangely, the kit instructions direct you to drill out the holes for the gun travel lock in the upper rear hull plate (part A1) though the travel lock was only fitted to IS-2s and not to any of the ISU variants (how would the crew traverse the gun to the rear?)  DO NOT open up these holes.

Note the comments above for the lifting rings, which should be carefully cut away from their mounting eyes and relocated in a more natural position.

In Step 7, you must choose whether to mount the 122mm or 152mm main armament.  If you wish to build an ISU-122, follow Step 7 from the supplementary sheet to attach the weapon; if you wish to build an ISU-152, complete Step 7 of the main sheet.  Note that several small components such as the hinges for the rain guard (parts D14) and the lifting hooks (parts B24) are shared between both versions.

The splash guard on the glacis (part A9) is overly thick but can be easily thinned down with a sharp hobby knife or sanding stick.

The kit includes an 11-part assembly for the 12.7mm DShK machine gun on the commander's hatch, which was present on most vehicles after the end of 1944.  Steps 4, 5 and 6 of the supplementary instruction sheet deal with the assembly of the machine gun, which is then mounted on the hatch in Step 7 of the supplementary sheet.

The kit provides six marking options:

• JSU-152 Chinese PLA Artillery Regiment, 1951
• JSU-152 Guards Heavy Assault Gun Brigade, near Berlin 1945
• JSU-152 Third Baltic Front 1945
• JSU-152 Polish LWP 13th SP Artillery Regiment, Warsaw 1945
• JSU-152 Soviet Heavy Assault Gun Brigade, Berlin 1945
• JSU-122S Tank Destroyer, Soviet Army, Poland 1944
  

The kit instructions describe 'heavy assault gun brigades' though the RKKA typically referred to such units as 'Heavy Self-Propelled Artillery Brigades'.