Nice project and choice for a conversion.
If you want/need a quality 6.5mm, there is one more cartridge to consider on the other end of the spectrum based on the 8x87 Mauser, rimmed and rimless. The 6.5x57 is a great performing cartridge. Commercial ammo is available by Sellier and Bellot, quality brass by RWS, loads of bullet options, and modern powders really give it a new level of performance. Bolt face and magazine feed do not need modifications.