Cannot use "new" keyword on class inheriting from MonoBehaviour

I have a class called ShootBulletPlayer.cs and in it I have a Gun class (which doesn't inherit from MonoBehaviour), and two types of guns that inherit from it: StandardGun and PushBackGun.

 public class Gun {
     public string prefabLocation;
     public GameObject gun;
     public Bullet bullet;
     public Gun()
     {
     }
 }
 
 public class StandardGun : Gun
 {
     public StandardGun()
     {
         prefabLocation = "Prefabs/RayGun";
         bullet = new Bullet.StandardBullet();
     }
 }
 
 public class PushBackGun : Gun
 {
     public PushBackGun()
     {
         prefabLocation = "Prefabs/RayGunV2";
         bullet = new Bullet.PushBackBullet();
     }
 }

As you can see, each gun has its own special bullet it's referencing upon construction which has its own unique properties. I get the following error when I create each bullet in each specific guns constructor: "You are trying to create a MonoBehaviour using the 'new' keyword. MonoBehaviours can only use added using AddComponent()" I know this is because my Bullet class inherits from MonoBehavior and therefore I should not use the "new" keyword to create a new instance of each bullet, but I don't know any other way to assign a new bullet to each gun upon its construction. Here is my bullet code which is located in a class called Bullet.cs:

 public class Bullet : MonoBehaviour{
 
     public GameObject bulletObject;
     private float pushBackAmount;
     public float shotSpeed;
     public string prefabLocation;
     public float spawnDistanceFromGun;
     
 
     public class StandardBullet : Bullet
     {
         public StandardBullet()
         {
             pushBackAmount = 2f;
             shotSpeed = 100f;
             prefabLocation = "Prefabs/StandardBullet";
             spawnDistanceFromGun = 2f;
         }
     }
     
     public class PushBackBullet : Bullet
     {
         public PushBackBullet()
         {
             pushBackAmount = 5f;
             shotSpeed = 100f;
             prefabLocation = "Prefabs/PushBackBullet";
             spawnDistanceFromGun = 2f;
         }
     }

} As you can see, each bullet has its own properties like "pushBackAmount" and "shotSpeed." How can I create a new bullet in each gun's constructor so that the variables like "pushBackAmount" and "shotSpeed" will be correctly passed?