This mount is not a direct drop-in component and will require fitting. EGW red dot sights are designed to be installed from left to right, with the muzzle facing forward. The dovetail features a progressive taper to facilitate easier installation. To mount your Vortex Viper/Venom, Burris FastFire or Docter red-dot sight, simply remove the rear sight from your firearm and replace it with the EGW mount. The mount can be removed and the rear sight can be reinstalled at any time. Mounting hardware is included. It is recommended that EGW products be installed and inspected by a qualified and competent gunsmith. This mount necessitates installation and is not a direct replacement, it is specifically engineered to substitute the rear sight for attaching Vortex Viper/Venom and other compatible red-dot sights A qualified gunsmith should perform the mount installation, which includes detailed instructions and all necessary mounting hardware The mount is specifically designed for firearms featuring oversized Novak cut dovetails, measuring 0.007 inches larger than the standard Novak cut