This is as close to twins as I get.
There are dozens and dozens of Lee Enfield variations, they may look alike to the novice eye but they are different. Same can be applied to the Mauser line of rifle on an even larger scale.
I have a small collection of Yugo Mausers and that can end up to be a dozen or more if you get the different variants.
Look at all the different Garands, Carbines, 03's, 03A3's and M1917's. That could be several dozen different rifles.