Originally Posted by D.Camilleri
Berger has reloading data available for free download on their website. I was a bit surprised how conservative the loads are. There is also a good read attached from Brian Litz about oal and how extending it allows for reduced pressure, more velocity and more powder. I was a little surprised to see that myself and most of us here are 7 or 8 grains of powder over their recommended max on 300 grain pills.
I have heard that many manufacturer's data sets have evolved to be much more conservative over a few decades presumably due to litigation liability. However, one might also presume that it may be due to the evolution of more efficient powders. I can't speak from any personal knowledge, but simply spewing info I have read out there. In my own case, I have had some Nosler loads produce higher velocity than what the manual shows it should being about the max velocity when I am loading for the mid range and also resulting in a tight bolt. That being the case, I would have no intention of going to the max on that specific load. That being said, I measure every single case and the powder digitally to eliminate any danger. Of course, if you have guys have a working load and it has been safe, can't argue with that, but you can certainly see why a manufacturer would be conservative in their figures.