Differences in published load data

[JimFromTN]

I have been reloading 300 win mag using 200 gr nosler partition, 70 gr h4831, CCI 250. According to Nosler, the muzzle velocity should be somewhere close to 2900 fps. According to Hodgdon, the muzzle velocity is somewhere in the low to mid 2700s. The difference is probably somewhere in the neighborhood of 120 to 150 fps. I went out today and chrono'd the round and the average velocity 2700 fps.

 

[Urban_Hunter]

Could be the test rifle used, the brass used, the primers used, length of barrel, testing conditions, etc etc.

 

[DaveB]

I use the book numbers as merely a guide. Some of the books have numbers that match my own chrony experience, others are off a coupla hundred FPS and they are always LOW, which makes me question my own loads and chrony.

I pay a lot of attention to bolt close and open effort. Next is primer cratering. I get a load that requires a bit of effort to eject I back down no matter the FPS. I am so in love with my fingers.

 

[WGK]

Sound advice Dave.

 

[Deer Assassin]

Could be the test rifle used, the brass used, the primers used, length of barrel, testing conditions, etc etc.

ditto