I carry my S&W 340sc in a Ryan Grizzle tuckable IWB most of the time. Even on days I wear a lightweight polo shirt that needs to be tucked in, the 340 disappears in this holster at around 3:00.

I personally don't like carrying the 340 in a suit jacket or blazer jacket. Even as light as the 340sc is, the weight is enough to cause my jacket to move in an unnatural manner. I much prefer carrying IWB or even in a strong-side pocket holster.

Now, if I'm wearing an outer jacket/coat, that's a different matter. I'll often put my 340sc in an outer coat pocket.