1-7in twist is my preferred rifling for the .223 Remington. I like heavy for caliber bullets in the .223 for all but varmint hunting. I use 62/64gr Speer GD, 77gr SMK, and 80gr A-Max.
I?ve killed a ton of deer and pigs with the .223 Remington. Just like anything else, shot placement is important, regardless the tool.
"To Hell with efficiency, it's performance we want!" - Elmer Keith