Interesting and helpful comments

To clarify, the starting point is a barreled action and a butt plate. All of the wood was trashed when it was sporterized. I would not be in favor of modifying an intact gun.

Bindi2’s points are well taken. I see coming up with an appropriate forend as my single greatest challenge, other than the posted question. If I were fortunate enough to find the right sporterized forend that has been cut beyond the band, I could do an extension with a hidden splice. I have done that quite a few times on Long Lees and carbines. Monetary value on completion is not a consideration for me. I probably chose my words poorly with regard to rarity. My intent was to say Mk. III’s with long range sights are rarely seen (not rare) in the market today – at least in my experience.

Roy, I would very much like to see pics of your BSA 1908. I am sure others would too. I would especially like to see close-ups of the palm swell area.