I would like to suggest the Leichte Selbstfahrkanone short L.S.K. a self propelled gun of the 1930 and is the competition vehicle by Krupp to the WD Schlepper 50 Ps 7,7cm FK 96 n.A. L/27 WD Schlepper 50 Ps
Overall its similar, but better and bigger than the WD Schlepper 50 PS, as its not just a gun on a traktor, instead a purpose build vehicle.
It would give an interesting and fun playstyle to the lower brs with a relativly strong gun, on an relativly small but mobile chassis with just enove armor to stop mg fire from the direction you are facing.
Beeing overall fairly unique beeing one of the few vehicles of the interwar period that was build and has the 7,7 cm FK 96 L/27 n.A. With beeing perhaps the 2nd vehicle with a gun and ammo without a tracer.
The vehicle is noted sometimes with the 7,7 cm FK 96 L/27 n.A. (same as the WD Schlepper 50Ps) and an 7,5 cm FK L/25, however i wasnt really able to find out more about it and the stats that i did find were identical to the 7,7 cm FK 96 L/27 n.A. example the velocity of 465m/s, so overall the FK 96 n.A. is more reasonable and realistic.
7,7 cm FK 96 L/27 n.A. in a new dedicated mount with 15° horizontal traverse and -10° to +40° elevation (or also -7° or also up to +70°) with 76 rounds stored at the back.
The available ammo:
K.Gr. 15 m.P. Saphe 6,85 kg 230g Fp.02 465m/s and 51mm/10m penetration (no tracer)
K.Gr. 15 m.P. m.L. Saphe-T 7 kg 230g Fp.02 465m/s and 52mm/10m penetration (with tracer)
K.Gr. 15 He 7,1 kg 380g amatol or 270g Pieric acid 465m/s
L F.K.Gr. He 7,18 kg 930g amatol or 700g Pieric acid( ig x1,1=770g, IRL x1,2=840g) or 820g amatol with 75g Pieric acid. with 465m/s
If considdering the similarity, timing (around that time the full switch from 7,7 cm to 7,5 cm happened) and what i have read the 7,5 cm FK L/25 could be a rebarrled 7,7 cm Fk 96 n.A., it would then use the standart ammo such as:
K.Gr. Rot Pz Apcbc 6,78 kg 80g Fp.02 und Np.10 (102,4g) 465m/s with 68mm/10m penetration
and one of the many
K.Gr. Rot. He 5,83 kg 465 m/s (or more cince its noticeably lighter) 520g Amatol (520g aquivalent) (with A.Z.23 v (0,15)) (also with a different fuze with 6,62 kg available and a setting for saphe)
2 were build
Crew: 3 (Driver, Gunner, Loader (one of them is also commander)
Ground clearance: 300mm
Weight: 8910 kg (of the final modified full prototype with armarment and fuel up to 9100kg)
Engine: 100Ps/Hp by Daimler Benz (or Maybach O.S.5 at 1900rpm or 3000rpm)
Top speed 40 km/h
At the front including gunshield 14,5 mm
Sides 12 mm
Rear 10 mm
Deck 6 mm
Belly 5 mm
Walther J. Spielberger - Die Rad- Und Vollketten-Zugmaschinen Des Deutschen Heeres 1870-1945,
Thomas L.Jentz, Hilary Louise Doyle - Panzerjaeger (3,7 cm Tak to Pz.Sfl.Ic) development and employment from 1927 to 1941 Panzer Tracts No.7-1