on a ruger #1 I would definatley go with the 7mm remington. The 280's are sweet on a short action, but you have a single shot so there is no reason to go with anything but the 7mm. In fact if your getting a new barrel anyways you could go with a 26" and get into the STW if you're ambitious. I think that the best fit would be the 7mm remington though. Brass is easy to find and relitively cheap, ballistics are great, you can keep your barrel length at 24", and recoil is more than managable. I wish I had'nt sold mine.