My son and I are starting to reload for these two and we'd like to find one powder that works really well for both, if that's possible! Loading mainly for target shooting at this point, but IDPA matches could be in our future. Need something that is fairly clean burning and consistent when used in hot/cold weather. Any info appreciated!

Lots of powders will work well, don`t how many will do "really well" though. The 2 cartridges are at opposit ends of the pressure spectrum for handgun cartridges and the best powder at one pressure level may not be the best choice at the next.
That said, I`d look at Titegroup since you want something mostly for paper.

Clays

Been using up some odds and ends I've had around for a while, leftovers from 20ga shotgun work. HS6 in the 9mm and WSF in the 45 both seem to work well in their respective cartridges but once I'm out of them I'll be looking elsewhere. Anyone here used Auto Comp? We are trying to load something that approximates typical self defense ammo speed to allow us to practice with ammo similar to what we carry with.

Self defense ammo is usually high velocity/high pressure....making a single powder for both problematic. Power Pistol is an option, it gives high velocity with both 9mm/115s and .45/185s. Actually, in Speer data BlueDot is high on the list for some bullet weights, but it does not meter as well as PP does.


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Look at Accurate #5, versitile, clean, meters very well. Works well for both 9mm & .45 ACP for both cast and jacked bullets.

Try Unique! Thought of as the top powder for 45 ACP, and it works very nice in the 9MM Luger as well. Also, you can load any shotgun gauge you may want with this powder.

Jerry

Powders I have tested that worked well in both the 9mm and 45 ACP.

Bullseye. 4.5 grains Bullseye and a 230 LRN for the 45 ACP and 4.0 grains Bullseye with a 125 LRN in the 9mm.

W231. 5.0 grains W231 with a 230 LRN for the 45 ACP and 4.1 grains W231 with a 125 LRN in the 9mm.

Win 231 works well. I also have a bunch of Hi-Skor 700X and it works.

Another vote for 231. Load it in my 9mms and 45s.

I used 5.3 gr. W231 with the H&G 68 200gr. bullet in the .45 ACP during my PPC years (and still), and 4.0 W231 with the 125 LRN 9mm for fun now.

How you are doing your loading makes a difference in the powder that will work best for you.

WW231 and WSF both work well in powder measures for progressive reloading. They develop good velocity but not max velocity loads.

Unique has been better for me when developing max loads but it does not go through a powder measure as well so I seldom use it in those chamberings.

Using 5gr 231 in 9mm (124gr GD), 40SW and 45acp. All jacketed bulets.