It's... not ideal, no. Although it isn't as if the PPSh is particularly accurate when it's operated correctly, either. :)
Held one of these at a gun show once. I held it with the non-trigger hand on the wood part before the drum (saw it in a game (CoD WaW to be exact)). The guy there asked why I held it that way and showed me what he believed was the correct way and held it with his non-trigger hand on the muzzle past the drum. I thought that was odd cause the muzzle would usually heat up when firing and you'd most singe your hands unless I missed something and the barrel is isolated from the muzzle. Kinda went off on a tangent here lol my bad