This image shows a model of a self-propelled artillery piece on a tank chassis. The designation is "10.5cm K18 auf Panzer Selbstfahrlafette IVa". This was a German vehicle built in 1941. Two prototypes were produced, and both were used on the Russian Front in combat trials. Despite success against enemy armour, further production did not take place.
The model is a 1/76 resin kit made by US CASTS. Additions include an antenna, tarps, boxes, and cable.

Here's a German Nashorn SP gun in resin and metal, 1/72, made by Britannia Miniatures. This is a wargaming quality model, and I decided to complete it as a wargaming kit, i.e. out-of-the-box with little modification. As such, the four piece kit (track, track, hull, gun) assembles quickly. The resin hull comes with some interior detail and a lot of stowage (spare tracks and wheels, tow chain, tarps, crates); tools, headlights and gun cradle are also molded as part of the hull. It is cast cleanly with only a few small air bubbles. The only finishing work was sanding a small resin residue block off the bottom. The metal tracks needed some flash cleanup, and are right/left interchangeable, that is there is no difference in the inside vs. outside detail. The main gun itself is also metal.
I finished it in an amateurish winter finish, hand applied by the crew (with brushes or mops) on the hull, covering the summer panzergelb color. Decals were obtained from the spares box; instructions were not included in the bagged kit (not needed for assembly, but I always like to see specs, history, and painting suggestions).

At the Niebelungenwerke the solution to mounting the long PaK42 L/70 gun on a tank chassis resulted in this vehicle, the Geraet 558, also known as the "Panzer IV/70 (A, for Alkett)". Compared to the Panzer IV/70 (V, for Vomag, aka the Panzerjaeger IV) this tank destroyer had an unmodified PzKpfw IV chassis, resulting in the need for a taller superstructure to install the gun. Recently this vehicle has become known as the "Zwischenloesung" (intermediate solution), with the Panzerjaeger IV being considerd the superior design. Both were built from August '44 to March '45, with 278 units of this tank being produced.
The 1/72 resin kit is a donation from Fine Scale Factory. Very reminiscent of an ESCI kit, there were a large number of parts (for instance, each wheel consists of two halves). The casting quality is very nice, with only a few air-bubbles in the wheels. Decals are scrounged from spares, and the figure is one of the old Nitto tank commanders.
One of the most formidable tank destroyers of WWII, the Jagdpanther is a favorite subject among armour enthusiasts. Based on the successful PzKpfw V chassis, this vehicle carried the 88mm PAK 43/3 L/71.
This MATCHBOX 1/76 kit depicts a vehicle operating with the XXVIII SS Freiwillige Panzer Grenadier Division in Berlin, 1945. 392 Jagdpanthers were produced between January 1944 and March 1945.
A very small number, probably only 18, of these "38cm RW61 auf Sturmmoerser Tiger" (Sturmtiger) were produced and used mostly in defense of Germany. The 38cm mortar fired rocket-assisted projectiles; a winch was mounted on the superstructure to assist in loading. Total weight of the vehicle was 65 tons.
This model is a SKYTREX/FUJIMI hybrid. The former makes a metal kit of the Sturmtiger, but packaged the wrong suspension type. All photographs I've seen show the Sturmtiger with the late style steel-rimmed wheels, which are arranged in a different pattern than the earlier rubber-rimmed wheels. The hull was also a bit crooked, so I replaced the metal kit with parts from the Fujimi kit of the late production Tiger, keeping only the superstructure. The Fujimi kit is very nice, with plastic tracks that show proper sag and curve nicely around the wheels.

The VVK3001(H) was the prototype chassis developed by the firm Henschel to meet the requirements for the proposed Pzkw VI. The design was not accepted for a main battle tank, but two chassis were converted to self-propelled guns and field-tested during the campaign in Russia (one was captured by the Soviet Army and is now on display at Kublinka). Designated 12.8cm Selbstfahrlafette L/61 (or Panzerselbstfahrlafette V, and new references identify it under the name "Sturer Emil") the vehicle gave a good account of itself in tank-hunting units, one scoring at least 22 kills. Although an impressive-looking machine, the design was not adopted for production, thus being relegated to the category of interesting but obscure AFVs used in combat during WWII.
MILICAST has somewhat satisfied our curiosity for such oddballs with their release of this resin 1/76 scale rendition of the "Stubborn Emil" (I'm sure there will be more!). The kit had nice clean casting, interior detail in the fighting compartment, and a few small parts to boot. My package did not have instructions, so I had to consult reference photos for placement of all the parts, which did fit together nicely. I have only seen a few black and white photos of a vehicle in service, and did not see any camo scheme, so I assume the color is panzergrau. The selection of decals is an educated guess, and the figures are Skytrex PAK crew soldiers.