Hello gentlemen, new guy here. I'm researching my 44 1/2 Stevens
rifle. I think it was originally 25-20 SS caliber. Apparently
it went to England and was re-bored to 300 - 10 Rook. It has English proof marks and the barrel stamped G. E. Lewis Birmingham. It came back home and was re-bored to 32-40 Win.
I'm thinking it may have been a lend-lease rifle, don't know.
At any rate 25-20 SS ammo was probably scarce if not available at all and so was changed to the 30 - 10 Rook. I don't have any info
on dates all this transpired.
Any info would be greatly appreciated.

John ...

Stevens rifles were sold commercially in England they even offered some factory chambered in rook calibers.

https://www.cornellpubs.com/old-guns/item_desc.php?item_id=439
Here you can see G E Lewis offering many stevens and other american guns for sale.

Thanks 375, that gives me a starting point.

John