Back on topic: I've been through more than a few muzzle devices of 7.5 and 10.3 barrels.
The KX3 does a good job of redirecting blast, but it adds a bit of length and weight. When I went from a 7.5 with kx3 to a 10.3 with birdcage, I only added about an inch and lost a little over an ounce.