Re: rechamber question
jedi,
The 6.5x47 has too wide of a shoulder to do a straight chamber extension to 6.5x55 Swede. You would have to set the barrel back or go to a case with a wider midpoint such as the .260.
FWIW, I'm finding I can't push the same bullets out as fast with a 7x57 (with similar case taper to a 6.5x55) as I can the 7mm-08 because of bolt thrust. My suggestion is to go with a case that has straighter case walls. I'm not familiar with the 6.5 GAP but that is what I would look at.
If you needed a little more power, I would look at the 6.5 Bobcat (.250 SAV case necked up and improved{6.5x49}), the .260 Rem/.260 imp., 6.5x55 improved, and 6.5-284.
<span style="color: #3333FF">Edit:
6.5 Creedmoor is in there too</span>
One of the guys where I shoot in the winter made a 'new' .260 imp. Instead of just blowing the shoulder forward, he pushed the shoulder back to give a longer neck. It helps with barrel life some. He had success with it.