Load data deviations for 357 sig, etc..

[Cferrell82]

Can anyone explain to me why the load data for 357 Sig( among others) varies so widely . Western Powders lists the load data for Accurate No 9 powder and a 115 gr Nosler JHP differently than Nosler. Nosler has the 115gr JHP with Accurate No 9 powder as having a different Max load which exceeds that listed by Western Powder themselves. Western powders lists the max load as being right under the 40k psi ceiling for that chambering. I have heard that although AA No 9 is a great powder, you have to be spot on with it or risk over charging.. Am I missing something here?

[swiley383]

Very common from manual to manual that’s why you need several sources. Go with the one that has the lowest starting grains and work up. Both sources are good data just work up slowly. Accurate powders work good for me though I don’t load 357 Sig. definitely start with the Accurate data.

Edited September 15, 2019 by swiley383

[frankmako]

each company does it own testing with their own testing equipment.  nothing is the same.  nosler uses their bullets.  western does not state what bullet brand they use.  little things can give different numbers in the data.  it is best to have many reloading books to look at.  i like to look at the older books for info.  start at the low end and work up.  get a chronograph to check you loads.  they are cheap and worth the money if you reload.  

[Quavodus]

Yeah, its not at all unusual to see manual to manual variations. The load I use in my .308 is 48.0 gr. Win.748 with 150 gr Hornady Spirepoint. One manual I got lists it as a max load and 2 others have it right about in the middle. Go figure. I've been using it for a long time, with no problems.