Weird Rayscast-Distances

Hello,

Based on some tutorial-material i made a small terrain to play arround and imported a first-person-controller. Now I've added an empty GameObject as a child to the Main Camera and added this script to determine the distance to certain objects:

 using UnityEngine;
 using System.Collections;
 
 public class MeleeSystem : MonoBehaviour {
     public int Damage = 10;
     public float Distance = 0;
     public float MaxDistance = 1.5f;
     public Axe Weapon;
     public AudioClip hitsound;
     // Use this for initialization
     void Start () {
         setMaxDistance (Weapon);
     }
     
     // Update is called once per frame
     void Update () {
     if (Input.GetButtonDown ("Fire1")) 
         {
             RaycastHit hitRayCast;
             Debug.DrawRay(transform.position, transform.TransformDirection(Vector3.forward),Color.blue, 30);
             if(Physics.Raycast(transform.position, transform.TransformDirection(Vector3.forward), out hitRayCast, Mathf.Infinity))
                 {
                 Distance = hitRayCast.distance;
                 if(Distance <= MaxDistance)
                     {
                         audio.PlayOneShot(hitsound);
                         Weapon.animation.Play("AxeHit");
                     }
                 }
         }
     }
 
     void setMaxDistance(Axe tool)
     {
         MaxDistance = tool.Length + 1.5f;
     }
 
     void OnGUI()
     {
         GUI.Box(new Rect(Screen.width/2,Screen.height/2, 10, 10), "");
     }
 }

As I said, I'm just starting to play arround... Right now I have the problem, that the values don't make sense to me. When i look down straight, I get 0.12 as distance, but when I highen up the angle just a little I get 5.82... I've added an screenshoot to ilustrate my problem.

Can someone please explain this to me? Google didn't help so far.

Greetings