I don't find any guns "intimidating" that aren't pointed at me. And as others have pointed out, ANY gun that is pointed at you is extremely intimidating.
Many years ago while sitting in the passenger seat I had a large silver revolver suddenly pointed at my face from a range of about 3 feet. I hit the floorboard while yelling at my partner "Go, Go Go!".
Never found out exactly what the gun was, but I still distinctly remember seeing the rifling in the bore. My impression at the time was that it was somewhere in the neighborhood of a 3" or 4" howitzer.