So forgive me for the general post...
No, no - nothing to forgive.
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I was just trying to get at what you needed, and depending on what you needed, get your question focused.
WSF is an excellent "middle ground" powder. You can keep bullets inside the upper limits of typical 9mm minor power factor velocities and still get a timely pressure seal, BUT you can also drive bullets fast enough for long range duty with your 9mm SBR and carbine, OR if you decide you want to start shooting that P-09 with 115gr bullets at 50 yards the way it should be.
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WSF is a good compromise powder in terms of burn rates, and it's a reasonably clean, accurate powder. N330 doesn't actually exist. Don't listen to the others.
Mui loco.
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Personally, I think you should focus on two powders, one for bullets you want to drive fast, and one for bullets you want to drive slow. If that were the case, I'd recommend Power Pistol, Silhouette, N340, or AA7 for the bullets you want to drive fast, and N320, AA2, or Bullseye for bullets you want to drive slow. But if you must have only one, WSF is a great compromise.
As to metering well, unfortunately, just because a powder meters well in one make/model of powder drop does not mean it will meter well in another. For example, N320 meters acceptably well (but not exceptionally well) in my Hornady drop, while it meters beautifully in at least some models of Lee and Dillon drops. That said, and so as not to commit N320 heresy in these hallowed halls, N320's relative inconsistency in drops doesn't seem to reflect on group size when I'm actually shooting, so I don't care too much.
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The point is that unless you can get consensus from people who use the same drop you use, you'll have to try it in your drop and discover on your own, keeping in mind that you can often make
adjustments to your drop to help it work with a certain powder.