Re: Re- rifle a Kreiger barrel
I think that the best you could do with the combination that you have is have a good smith fit the barrel to your action and chamber it for the 7mm mag case necked down to .277.
You already have the 7mm mag brass, all it would take is some dies and you'd be shooting your new .277/7mmMag wildcat.
You can't open up the bolt face since it is already the large magnum bolt face. The .270 has the .308/.30-06 bolt face is smaller.
Unless you buy a second bolt, you are stuck with using magnum size brass.
Like previously mentioned, I also think that the bore diameters are too similar to rebore and re-rifle. The only time it would be practical IMO is when there is sufficient sentimental or historical value, and the original barrel markings need to be preserved, and you want to be able to continue shooting the piece.
Paul