I have been in Sierra and PMC ballistics Labs.
Published data only applies to their barrel, and their lot # of powder, AND other components.
Published data is only meant to act as a GUIDE, not what would be safe in everyone's rifles.
Start lower, work up to max load, watch for pressure signs.
We that have some grey hair have all experienced HOT LOTS of powder, barrels will differ in throat length, and bore dia. Components are manufactured with a +/- in variances.
I have found many times that the "MOST ACCURATE" load in a nosler manual was very, very close to my barrels, but care must be exercised if their most accurate load is their stated Max load.
Their advertised velocity means nothing to me as this number with my loads and my barrel will always vary.
So, as AR launch stated, a reloading manual is meant to be a GUIDE ONLY....not gospel carved in STONE! Learning to think for yourself starts with reading a lot in the beginning of the reloading manual, then read it again.
Zastava223rem, an accurate load in several of my Rem 700 7 Mags is 63.0g of IMR 4350, Rem case, with a rem 9 1/2 primer. Velocity varies with different barrels. The Mack Daddy load for the 150-154g bullets is with R#25, Winchester Mag primer(!!***), at 3250 out of numerous 26" barrels, bullet within .003 of the lands, SD of 7-9 fps, bug hole accuracy.
