Very nice!
I have been more than mildly curious with the 275 Rigby given my proclivities to the 280 Rem through the last 35+ years. I've owned a couple 7x57 and think they make ideal medium game cartridges despite Mr. Bell's usage. I've threatened to build one for a while. I'd prefer it stamped 275 Rigby, gives it a bit more panache......
Have you considered the 7x64 for panache ? No point making it easy
, or too practical.
Just a thought