Different manuals can give wildly different load data. I tend to look at all of my manuals and consult any information available from the powder manufacturer. I tend to look at all my data sources and try to find some common ground.

There will be tons of variances depending upon weapon, brass, primer, bullet, and seating depth of that bullet, and even case mouth crimp. This is why it is best to start with the starting load and work up. Never start at or very near the top.