I have a WR takedown in .318 which I love. It has a Griffin & Howe mount with modern scope. It likes the traditional 250 gr bullet with the unbelievable ballistic coefficient. It is a wonderful plains game round and were it legal, I would not hesitate to shoot a buff with it.
I had read your earlier post about having bought a Westley Richards .318. It is heartening to note your satisfaction with it as a plains game round and your unhesitating endorsement of it for use on buffalo.
Ken Waters acquired a Westley Richards .318 bolt-action rifle in the 1960s, which had badly worn rifling. He had it rebored and rerifled to use .358 bullets. Read 'The Story of a Rifle', pp. 61-3 in Gun Digest 1985 (39th ed.) and you will see that it appeared to work out quite well.
I have used a 318 W-R on a plains game hunt in South Africa many years ago. I have also killed a few wild pigs hunting in California. I think it is a wonderful little cartridge using on game as large as an Eland. I would have no problem using it again as a primary rifle on planes game.
Mule deer and Colorado elk seasons almost done! Hunters driving farm roads, looking for racks, their PH driving them along, I ask that you not pull into my drive. The buck behind me, on the boundary line of the GMU somehow knows. The hunter laughs, I would invite you in to see my Searcy rifles but social distancing prevails, darkness arrives and the buck slides away into secret tree grove...