What do you think of 10,0grain alliant power pistol behind 116gr Norma JSP and CCI 550 and federal brass?? Is it too much? Thank you for your help.

I would consider that a max load...

Sounds like you're looking for max power? I would think Blue Dot would be a better choice.
BD is much slower burning and with large capacity necked case like the Sig it would seem ideal to me.
Just a thought...

The load you suggested sounds fine, but I don't know about the primer, maybe a 500 instead? I always use the 550 myself but I use Blue Dot or slower powder (9mm, 38spcl, 357mag).

I assume you got that load from the Alliant table (Shows 10 grs of PP, 115 gr jacketed, 37K psi, 1500 ft/sec). I don't know what gun they used, but this seems to be very hot. I am using 9.5 grs PP with the 100 gr Hornady FMJ and it seems to be equal to factory loads in every respect.

I would approach with caution and start with 8.5 grs of PP.

i have used up to 10 grains of power pistol in a 357 sig p229 with a 125 it is a little over but shot great.might not be safe your own your own there,thanks,keith

The best powder that I found for velocity in the .357 Sig is AA#9.