I do not know about the 308's, but the 223,s have a long throat. Most bullets suitable for the twist rates of the Handi will not reach the lands. I can reach the lands with a 60 grain V Max, but I have found that it shoots best off of the lands. Most people are quite a bit away from the lands with their hand loads. Start with standard OAL and find your best load, then experiment with bullet seating. Chances are you will find a jump of .100 or more will be best.