While the title and Frank Castle both refer to Karen's gun by its caliber as a .380, the weapon shown appears to be a stainless steel Taurus PT-92 AFS, which is a 9mm gun, not a .380. Note that the weapon being referred to is available in multiple calibers, including a full size .380 model.
In the dinner, Frank asks for "Black Coffee", presumably for the caffeine. The waitress brings over an Orange rimmed coffee pot, which usually designates De-caffeinated coffee, not regular.
When Daredevil jumps out of the window to save Claire, even though he is trailing his hand down the rope, and she is free-falling, he actually falls faster than she does. This is impossible by the laws of physics.
At 49:15- The henchman slides his sword across Daniel Gibson's prosthetic arm until it "catches" in the groove where the blood will begin to flow.