Alliant -vs -Nosler data 300 win and Rl23

[284allways]

I noticed that the Alliant web shows 76.7gr (max) of RL23 with 180 gr Partitions and Nosler 9 lists 73.5 as max ??Why would this be such a large delta ? What am I missing ?

 

[DrMike]

Differences in barrel length, seemingly minor differences in chamber dimensions and slight differences in bore size account for some of the differences. Temperature differentials no doubt contribute significantly, though laboratories usually attempt to maintain standards to eliminate this variable. Then, lot-to-lot variations in propellant, primers and brass contribute significantly to observed differences. This is a good opportunity to remind especially new hand loaders that this is the reason we don't simply pick a powder, but we test the powder, reading the firing and the brass to assure ourselves that a load is safe.