Tapconing into a mortar joint is to be avoided. 

See the discussion [here](https://diy.stackexchange.com/questions/51888/what-masonry-anchor-should-i-use-to-install-both-window-boxes-and-shutters-into). 

And the one [here](https://diy.stackexchange.com/a/104159/23295) about how 3/16" are garbage. Use 1/4".