Joe,
H&R didn't start making 1:9" twist 223 barrels until 2006, so unless your barrel is an accessory barrel, it's 1:12", but you can easily check it yourself with the instructions below the twist rates in the FAQs. If it's a factory fitted barrel, the last 3 digits of the frame serial number will be engraved in the left side of the barrel underlug.
Some members have had good luck with 60gr-64gr in the 1:12", the 60gr Vmax, 63gr Sierra Varminter #1370 and 64gr Win Power Points are those that I'd recommend you try, the 60gr Partition may also work.
Barrel fitting info can be found in the FAQs if a barrel doesn't fit, it also tells you what how to tell if it fits properly, there's no guarantee one will fit, it may or may not, some do, some don't.
Tim