I have acquired a medium sized Farquharson action, sold by Griffin & Howe, presumably sourced in England. It has a 303 British extractor at the present. I want to build a classic British style stalking rifle, in a vintage but reasonably obtainable caliber. Can this action even be used for a rimless case or a belted case like 300 H&H. I would also consider 275 Rigby or 375 H&H Magnum flanged. Another consideration is salability when I’m done with it. Any advice?

I can't comment on the strength of the action. But I would build a 303 British or possibly 30-40 krag, either would require no modification to the extractor. If you want a heavier hitter, 405 winchester is the same rim diameter as well. 303 would likely be more saleable of the three.

The action is strong enough for any reasonable cartridge. I would stick with a rimmed round, preferably a British cartridge in my mind, hard to beat the .303 really. Build away...I have built several and have a pile in process for clients and for myself.

I have an original Holland built in .30 Super Flanged, a great cartridge.

English rifle, English chambering. 303 Brit.

I’m very much inclined to 375 H&H flanged magnum with good irons and Talley bases just in case. If I can find someone to make it, a short rib with Talley bases machined into it will be my choice. A banded front sight and barrel band sling swivel base would complete the package. I have some good aged Juglans Regia blanks to choose from and a stockmaker who is willing.

I like the choice of a .375 Flanged, although a smaller medium bore like the .275 Flanged (7x57R) or .303 is arguably more practical and therefore re-sellable.

I recommend considering a 400/360 or 400/350.
The 360 is just about perfect in a medium sized Farquharson.
The 375 Magnum Flanged is also great but might be more difficult to source components for.
Bullet selection for the 350 is endless - less so for the 360 or 375.

I want to use a British cartridge but I have plenty of 303 guns already. Maybe 275 Rigby rimmed.

Not sure why 375 Flanged Magnum would be difficult to source components for.

I use RCBS dies, Norma brass and you can buy Norma ammunition.

What’s not to like!

375 Flanged it is. Douglas barrels said they will fit a barrel to the action and chamber it, plus modify the extractor. I have a bunch of new Norma brass, dies and plenty of bullets. I’ll looking at a 26” No 5 Douglas profile with 1 in 14 twist. I’ll need to find a smith to install front sight, barrel band sling base and a 1/4 rib. I plan on some minor engraving on the small parts, no engraving on the receiver as it’s in good shape now. I have an old smoky, highly figured piece of Circassian for the stocks.