I'm having troubles using a Capsule Cast

I've started to add different guns to my game, most recently a shot gun, up until recently I've been using raycasts to detect if I'm shooting something, which is fine for most guns, but I wanted the Shotgun to have more of a spread, so you don't have to be as accurate, so I looked up how I could somehow widen a Raycast, I've found out about the Capsule Cast, which can do exactly what I wanted.

I'm having problems using it though, with some guns, it works great, but with others, the accuracy's way off, way above or below the crosshair.

Here's my code:

     shooting = true;
     RaycastHit hit;
     Vector3 directionRay = gunMuzzle.TransformDirection(Vector3.forward);
     //Vector3 capsulePoint2 = gunMuzzle.position + directionRay;
     Debug.DrawRay (gunMuzzle.position, directionRay * range, Color.red);
     if (bulletsLeft > 0 || isMeleeWeapon)
     {
     if (Physics.SphereCast(gunMuzzle.position, spread, directionRay, out hit, range))
     {
         if (hit.rigidbody)
         {
             if (hitParticle)
             {
                 hitParticle.transform.position = hit.point;
                 hitParticle.transform.localRotation = Quaternion.FromToRotation(Vector3.forward,
                     hit.normal);
                 hitParticle.Emit();
             }    
             hit.rigidbody.AddForceAtPosition(directionRay * force, hit.point);
             hit.collider.SendMessageUpwards("ApplyDamage", damage, SendMessageOptions.DontRequireReceiver);
                 if (isMeleeWeapon)
                 {
                     audio.PlayOneShot(reloadSound);
                 }
         }
         else if (hit.collider.gameObject.CompareTag("Kruncanite"))
         {
                 if (!bloodEffect)
                 {
                     bloodEffect.transform.position = hit.point;
                     bloodEffect.transform.localRotation = Quaternion.FromToRotation(Vector3.forward, hit.normal);
                     bloodEffect.Emit();
                 }
         }
     }

What am I doing wrong?