Its the size of the bullet that the gun is made for. its the caliber that a handgun uses
Revolver, made in Germany, buffalo on the grips? $75-$100 in very good condition.
A 22 LR caliber pistol made by Walther, it is similar in design to the Walther P99.
S&w
The ONLY .35 caliber pistol I have seen was the Smith & Wesson .35 Automatic. This is a rare gun, and was only made 1913-1921. Sure you don't mean a .25 caliber pistol?
Impossible to answer without knowing who made it and what the caliber is.
Yes, they made many of them.
No sn data available.
Around 1931
No such weapon made by Walther.
25-100
The company that made it or the dealer that sold it to you can find out what kind of pistol and know the calibur.