Powder charge recommendations from different sources

[Rag Horn]

Here are published min/max powder charge weights for 150 grain bullets from 4 different companies. Why does Sierra allow for nearly 8% more powder than Hornady? I struggle to believe bullet construction alone accounts for this. Strictly in terms of chamber pressures why wouldn’t all 150 grain projectiles be the same? Does a manufacturing variation in magnum primer makers account for 8% powder charge? Does bullet alone seating depth account for that?

Hornady 

58.8-65.5

Sierra 

60-70.4

Nosler

64-68

IMR 

62-66.2

 

thanks for all the reply’s on my last post about reloading for a 7mm rem mag

[dse]

Capacity of different cases very greatly

[galiuro mountain man]

It is probably listed that way by them because that is what will fit in the case with that certain powder.  I like to look at hodgdon website for hodgdon, winchester and imr powders because they show what pressure a powder is at min and max. I generally use the numbers as reference, and make sure to start a load at or just above minimum (some powders, especially slow ones can have a large pressure spike below minimum).  

Start around minimum and do some work up to find accuracy.  I have some loads that are well above max, but do not show pressure, and some that show pressure signs a grain below stated max.

 

[Rag Horn]

4 minutes ago, dse said:

Capacity of different cases very greatly

I didn’t check to see what casings they listed as test casings. I’ll have to go back and look at that. See if they published that info. Thanks. 
 

[Delw]

also different books and online factory data will have the same powder same bullet and way different loads. some vary 2.5 grains in a .223 for max load.

[452b264]

Theres a big difference in jacket thickness between a Nosler Accubond/Partition and a Sierra gameking, Hornady SST.