I haven't got one now but what model of Leica would you be intending to use it on? Although an R3 is technically a 3 cam jobbie Tamron gave out a specific warning when they still sold them that the R3 usage was not guaranteed. They were designed for the R4 and later models.

Indeed, I was only ever successful in using a Tamron 24/50 zoom and the 80/210 on my R3, but with the R4 all the Tamron lenses I had at the time were OK.