SniperAce016: JPro is exactly right in his assessment of individuality among Rifles.
But I am going to give you some particulars on an extremely accurate loading I used a short time ago in my Remington XR-100.
With this loading I used produced/shot the smallest group (5 shots at 100 yards) I have ever shot with an factory stock Rifle (non-40X type Rifles anyway).
The group (5 shots at 100 yards) measured .121"!
I have been shooting groups for going on 50 years now and this loading IS accurate - as I have used it now in several other 223's!
223 Remington accurate loading components: LaPua 223 Remington brass, Federal 205 M (match) primers, Berger 52 MEF grain bullets and H 335 powder!
Best of luck in your "future" load testing.
Hold into the wind
VarmintGuy