How much is too much?

[johngalt]

I don't load 9mm, so I can't help with that specific cartridge, but questions about differing data from varying sources are asked frequently.

Some points to keep in mind to help resolve those differences:

* Powder charge is just part of the recipe. OAL is also important. Given the same bullet, seating deeper requires less powder to achieve the same pressure.

* Different bullets, even if they weigh the same, can have different shapes, and therefor AOL. A recipe that uses your specific bullet is better than one that just says "n gr bullet".

* Lead, Jacketed, and Plated bullets use different recipes.

* When trying a new recipe, start low and work up. Just load a few cartridges at each charge.

The sources I use, in order of preference:
* For jacketed and swaged lead, the bullet manufacturer (I shoot mostly Hornady bullets)
* For hard cast, Lyman
* The powder company (Alliant and Speer now use the same data)
* Lee

 

[BennyS]

I have five reloading data manuals, when I'm in doubt I go to the bullet manufacturer

 

[rwsmith]

Also different shaped bullets....

* Different bullets, even if they weigh the same, can have different shapes, and therefor AOL. A recipe that uses your specific bullet is better than one that just says "n gr bullet".

Yes indeedy. Different shapes/styles of bullet also differ in 'bearing area' that actually touches the lands and groove, giving differences in friction. I usually just try to get as close as I can between bullet and manual data and work up. Not the most significant factor but it does pay to know this.