I have carried the exact same way for many years and have never had a problem. You just have to make sure your sheath has good retention but, most have more then enough. This way is by far the most comfortable fixed EDC method for me.I jest. Not a method I've tried. I usually go horizontal for concealed. You've got to have the utmost trust in your sheath for that kind of carry.
What is this one? Smith-something?
Thanks,
B