AddTorque seems to give the same rotation regardless of input vector

Hi everyone! I'd love some help on this, because I'm stumped.

I'm firing off a bunch of cylinders to use as ejected casings for a blaster. I add a random force to each casing after it's created, which works fine, but when I try to add a random torque it seems to result in the same rotational speed no matter if I add (0,0,10) or (0,0,1000).

The relevant scriptpiece, here I've just written 2000 to check if anything happens:

casing = Instantiate(cartridge, weapon.transform.position+Vector3(0.22,0.4,0), Quaternion.Euler(0, 0, 90));
Physics.IgnoreCollision(casing.collider, collider);
casing.rigidbody.AddTorque (0, 0, 2000);
casing.rigidbody.AddForce (Random.value*10, 20+Random.value*20, 10+Random.value*10);
Destroy (casing, 3);

The casing object has a mass of 0.1, a drag and angular drag of 0, no kinematic, interpolation or freeze rotation.

The amount of spin is limited by the Max Angular Velocity in the Physics Manager. By default it's just 7.