kiwi**

Hi My 223 is the same rifle and the barrel twist is 1-9 and favours the 60gr hornady GR HP Bullets and groups a times around 5/8 at 100metres with 23.5gr of adi 2206 powder . Also loaded up some sierras 63gr semi point with same powder but 24grs works good also. The screw tension holding on the forearm also makes a difference to groups. Hope this helps. Regards Kiwi**