My first custom rifle
will be a .280 ackley. I have done a gob of research on it and I love what I see. It is like a .243s big brother. Supposedly all the benefits of a 7mm mag but without the severe recoil.
The case is easy to form also if you have the chamber cut correctly. A factory .280 rem should fit snugly (slight crush fit) from the boltface to the shoulders. Then just pull the trigger. (safety first). Many of the people I have coresponded with about the round have gotten sub .75 MOA with the .280 remington rounds as they were fire forming them!!! What a great deal. Get great performance for the first year or two while fire forming brass and then get superb accuracy the next couple of years with custom made once fired brass.
You win, and then you win again. WOOHOO!!
Oh, one more thing. My buddy "Dave in Idaho" has a rifle in 6.5 Gibbs and likes it alot. He has fired several thousand rounds through it and is pleased as punch.