Exactly right Bobco....340' s are stiffer. At the time I shot 400' s I couldn' t make them any shorter and didn' t want to go lighter on the point weight. So, I opted to got to the heavier spine for ease of use, so to speak. Now, I couls probably shoot the 400' s with ease since I just put a new rest on and can lop off at least 1.5" . I just bought a dozen ICS camo shafts though and they are tuned, so next year at the earliest I' ll think about changing them.