The beauty of the K-Hornet is its ability to also fire 22-Hornet, which may be purchased as factory ammo or handloaded. Once the 22-Hornet has been fired in your K-Hornet barrel, it becomes fireformed K-Hornet brass. Given that you reload, you will have both options (K-Hornet is not available as factory loads). As far as which is better - the K-Hornet or the 223 - up to about 150 yards they are comparable in accuracy, though you may find the K-Hornet cheaper to reload. Beyond 150 yards I have to give the advantage to the 223 which has considerably more velocity. For futher info on the K-Hornet I suggest you visit Rocky's web site at
www.reloadingroom.com/page28.html