Not that I want to be nit-picky, and it isn't even my scale, but …
This casting of a Solothurn doesn't do much for me. Most of the things I would look for as visual recognition points don't seem to be present, or if present don't seem to be prominent.
What I would typically look for:
1) Wheeled carriage. OK yes it could be removed. So it is not a necessity. But it is a fairly unique mark of the Solothurn gun. So why not put it in the casting?
2) Cylinder above the barrel -- I don't actually know if it was a recoil damper or recuperator. The cylinder was quite a prominent feature of the gun. When mounted on it's bipod, I believe the cylinder reached almost all the way to the bipod. It makes the gun look altogether more massive than this model appears to my eye.
3) Complex barrel assembly. The barrel of a Solothurn in general should not just look like a long pipe. It's a fairly complex assembly, recoiling in to the larger base assembly (telescoping), with the bipod (when mounted) placed at the junction of inner and outer assemblies, and with a significant flash hider. When combined with the recoil cylinder (above), the first part of the gun should be quite massive compared to the barrel jutting out at about the point of the bipod.
4) Magazine. This may just be the pic. The magazine extends from the left side of the receiver, IIRC pretty much right above the pistol grip / trigger. Makes the gun look awkward to shoot rifle-style, at least to my eye. This is a less significant issue than the three above, but contributes to the distinctive look of the gun.
Maybe it's the pic. But I just don't look at that and say "Oh look, that's a Solothurn". Even at my scale (6mm) I'd be a bit disappointed with such a plane pipe-on-a-bipod.
Your mileage may vary.
-Mark
(aka: Mk 1)