Projectiles won't fire correctly. Help! (C#)

Projectiles will only fire correctly between 42 and 50 degrees, any other angle that i have tried sends them either directly down or backwards. Please take a look at the code:

using UnityEngine;
using System.Collections;

public class Cannon : MonoBehaviour {
public GameObject projectilePrefab;
public int Angle = 10;
// Use this for initialization
void Start () {

}

// Update is called once per frame
void Update () {

}

void FixedUpdate()
{
    if (Input.GetButtonDown("Fire1"))
    {
        GameObject projectile = Instantiate(projectilePrefab, transform.position, transform.rotation) as GameObject;
        projectile.rigidbody.AddRelativeForce(new Vector3(0, 0, -1000));
    }
}

void LateUpdate()
{
    transform.rotation = Quaternion.Euler(Angle, 0, 0);
}

}

never use euler angles directly to rotate an object but rather use the Mathf.MoveTowardsAngle function - here you’ll find some insight and code to clear that up