If you don't like the way 4064 meters, pick up a pound of 4320. The kernals are smaller, so it meters nicely.
Out of my 18.5" barreled Remington M7, Re-15 and IMR4320 seem to perform best with the 120 gr NBT and TTSX. My nephew's Ruger Compact (20" barrel, I believe) shoots well with the same two powders. His also likes WW760.
And....I'll throw in with the majority opinion. The same powders that give top performance in a, say, 24" barrel will also be the top performers in a short barrel.
