Thanks guys.  Going to reload 500 rounds, 125 each at 10.4, 10.6, 10.8 and 11.0 and see what nets me the best accuracy and gives me a chance to look for over pressure signs as I go.

Dangit, I meant to put this in the 10mm data reloading sub forum, moderator can you move this please?  Thank you.

OK, I'll make this short.

I have 500 nickle once fired cases all ready to load.  so I pull out my handy dandy reloading books. My speer NO13, old as dirt, and my Lyman 49th, fairly new.

I have some 180 grain HAP bullets which are jacketed HP, so I look at speer for the 2 powders I have, Unique and Blue dot.

Speer says Blue Dot 10.0 to 11.0 and Unique 7.2 to 8.0

Lyman says Blue Dot 8.1 to 10.3 and Unique 5.8 to 6.7

this is a pretty significant difference. Advice please?

Also if it matters I will be shooting these out of a Glock model 40 exclusively.

And I will be measuring every single powder charge and an electronic scale.

Thank you.