I am looking at the case dimensions of the 270 win and the 270 weatherby mag. It looks possible to rechamber to the latter. What about bolt face and belt dimensions? Feeding problems? I want to do this to a CZ-550. I would have my gunsmith do the work.

You are talking about a conversion from standard to magnum.

1. Open bolt face to 0.532"

2. Re-fit extractor for larger rim.

3. Open rails with a file to let larger cartridge pass through and to get feeding right.

4. Maybe switch out follower for another.

Why bother? The 270 is a great cartridge, and the .270 Weatherby offers only about 200 f.p.s. advantage over it, at considerable cost in brass and powder.

If you really want a .270 Weatherby, why not get a Weatherby Mark V, or at least start with an action that was originally made for the large belted cases?