Is it possible, and does it make any sense, to rebore and rechamber a .416 Rigby to a .404 Jeffery? I realize beforehand that both cartridges are similar, but I have another itch if you know what I mean.
thanks
Rick

There's more involved than just a simple rebore and rechamber. The Rigby chamber is larger than the Jeffrey which would necessitate setting the barrel back. Hopefully you would have enough straight section at the chamber end to do this. Practically speaking (unless you have a quarter rib on the current barrel) it would be cheaper to rebarrel. Then you have the problem of the larger bolt face for the Rigby. At the very least you would have to replace the extractor. You didn't mention what brand of rifle it was. Overall, it doesn't sound prctical, especially since both rounds can push a 400 gr. bullet at 2400 fps.

Thanks !! That is what I needed to know.
Rick

No, not actually --- the rigby chamber is too big, but more importantly, you couldn't recut the barrel, as the .416 grooves would be be between the .424 and .412 or so bore.