I dont think the .410 was derived from the .44XL...
You are correct. The 44xl was an American dead end. It gave way to the .410. For a short time, they existed together here.
This is the 44XL. Several companies offered loadings. Marble loaded the 44WCF with a round ball and called it the Game Getter after their gun.
This is the 1st version with sights. Later versions were chambered for 410.
A later version
These came with barrels of various lengths, some of which are illegal today without a stamp.
Many makers offered guns chambered for the 44XL. Here is one of my 44XL sxs. This one is Belgian in origin. I also have an American made 44XL sxs.
There is also the myth that Parker made the 1st American .410 sxs.
Pete
