Great timing. I hope I'm not hijacking here, but I am looking for a load for my 308 Norma Magnum, particularly using 180 grain Failsafes. Anyone have a recipe that uses these bullets?
Loads that are listed for the 300 Win Mag are perfectly safe in The Norma. Case configuration is slightly different, but available internal volume is identical. Max OAL is the same. The only real difference is that the Norma is rated at a (very) slightly higher maximum pressure, but we don't go there, do we?
I own, and shoot, three 308NMs, and a couple of 300Wins. I work up all of my loads individually for each rifle, and was pleased to find that I came within one grain of powder (all other factors being held equal, same ullets, primers, neck tension, et al). This held true for each of the several powders that I tried in all of the rifles.
The thing is that I work up for optimum accuracy, which isn't always the same as maximum pressure/velocity. I assess my results on the basis of what happens at the chronograph and down range. I have not often had to go near the listed maximums. I do not like flattened primers, and really freak when a rifle blows up.
As to "needing" that extra 20fps, how dead is dead? The animals will be unimpressed by the slower bullet and will shrug it off, that's why it is no longer possible to kill anything bigger than a west coast blacktail with a 30-06, the big deer know that there are magnums out there and wait for them!