This is very definitely not meant as a criticism of reloading manuals/data, but they are necessarily imperfect. Load data are necessarily developed with a small number of firearms, generally one rifle for a specific rifle cartridge. The cost of developing load data using many different rifles would be prohibitive and the data would simply be different - not necessarily more accurate for any particular rifle. Reloading manuals are the starting point for developing the best reloads for an individual rifle and they provide information to help prevent us from going too far. We know that two identical rifles are not, in fact, identical. The barrel for one of them was made before the barrel for the other so there is likely to be an extremely small difference in chamber dimensions and bore diameter. A hunter using his/her own reloads must rely on his/her own hunting/reloading experience as well as manuals for their most effective, safe, and reliable loads. (As an aside, I have hunted exclusively with my own handloads for centerfire rifle cartridges for my entire life. But I am happy not to reload .22 Long Rifle.) Oh, and I agree with Crusty's post.
NRA Life Member - RMEF Life Member - Vietnam Vet