The VP40 is a part of the VP line chambered in .40 S&W. The HK40 dimensions are identical to those on the VP9 model. Three interchangeable backstraps and six grip side panels are part of the ergonomic pistol grip design used in the VP40. Molded finger grooves on the pistol's grip's front naturally place a user's hand for the best firing position. The pistol uses the HK P30 steel magazines, either 13-round or a reduced 10-round capacity. All metal parts, including the springs and pins, and the machined steel slide, have exceptional metallurgy and are protected from corrosion and wear by HK's hostile environment finish. The recoil pressures experienced by the user and the handgun are reduced by the employment of a patented captive flat recoil spring in VP pistols, increasing shooter control during rapid fire and extending component operational life.