JS to C# class conversion issue.

In US I had a HandGun class with properties that had no value, and then a Gun class that defined all of those values by programming:

HandGun.js

class HandGun

{

var name : String;

var ammoType : String;

}

M9.js

class M9 = new HandGun();

M9.name = "M9"'

M9.ammoType = "9mm";

and there are no errors. (I typed that up now so please excuse any errors)

But I am porting the code to C# and I have:

HandGun.cs

public class HandGun : MonoBehaviour

{

 public string name;
 public string gunID;

}

M9.cs

public class M9 : MonoBehaviour {

public HandGun M9 = new HandGun();

 M9.name = "M9";
 M9.gunID = "M9";

}

And i just cant find a way to replicate the effect. What am I doing wrong?