I had one in 303 British chambered for 32acp/ Made by the Marbles Co. that made gunsights also. Worked OK,,whats not to work! Accuracy was about 3" at 25yrds with most any ammo I ever tried in it. A novelty that soon became more of a PITA to load and reload.

They were made in alot of different caliber combinations. I think the 32acp also was chambered in 8mm Mauser & 303 Savage. Probably others too. The 32acp seems to work fine through a .308dia 30cal Bbl.

Winchester used to sell them with their name on them too but they were probably made by Marbles or someone else.

Seems like another company made/marketed these little adaptors back in the day but I can't recall the name. I think they're still made by a company or two. They never seem to quite go out of style completely.

Some of the old ones suffer from a split neck. Just old age or maybe newer higher pressure ammo used in them, I don't know.
There were larger cal adaptors using 38pistol rounds in 35cal rifle chamberings, 45Colt in 45-70, etc.