Re: 223 loads
In my Service Rifle, for 600 yard shooting, I load 24.5 grs of Varget behind an 80 gr Sierra MatchKing. At 200 & 300, same load pushing a 69 gr SMK.
The 69's can be made to fit the mag, but the 80's are loaded long, and used as single shot only. If you need repeat shot capability, forget the 80's, as you'll use up too much powder space if you seat them deep.
Depending on your needs, those are two great loads.