If I was you I would forget foxes untill you've had a few months practicing knocking over rabbits at different ranges upto 100 yards with a 22lr
Leave charlie alone untill you can guarantee a clean kill
Just my opinion but hmr wouldn't suit a beginner after foxes to much room for error
Get a 22 lr and get out as much as you can, then a cf just for foxes, gut shot or chest its going down, same can't be said with a hmr consistently