Anyone done this? Got a nice custom built by Alan Dees in 25-06 on a 1909 action, thinking a 6.5 swede would be perfect.

The case is to short. the 06 case is longer than the 55mm case.

I'd go .284, as in 280 A.I.

As noted previously, you'd have to set the barrel back, as the 25-06 case is quite a bit longer, 63.3mm, than the 6.5x55.

I would also question if a rebore of only 0.007" would clean out the current rifling, as it is common to cut grooves 0.004", which results in 0.008" greater diameter at the bottom of the grooves than at the top of the lands. A 6.5mm/0.264" bore is typically 0.256" at the top of the lands, just 0.001" less than a 6.35mm/0.257" bore is at the bottom of the grooves. While 0.001" is probably not an issue, it is a question that I don't know the answer to.

The smallest rebore that I've had done was from .243" to .264", converting a Savage 99F from 243 Win to 260 Rem.