"When I can get it, I prefer IMR-4198 for my 223 loads. 19 grains will put a 55 grain bullet into the 3,000 fps range..."

As I earlier mentioned, my favorite load is the 50 grain Remington bullet (actually closer to 50.5 grains) with 21.5 grains of IMR 4198. The last batch I chronographed from my 24" Savage had an average MV of 3228 ft/sec with a SD of 32 ft/sec.