Like someone else said if you plan to use it in the feild then get one of the models that "pivot" to compansate and keep your rifle level when used on uneven ground. How do you plan on shooting your rifle ie: prone, sitting ect, then I will recommend you a bipod with a part number and as said before get the Harris brand, without spending hundreds the Harris are the best you can buy as most of the Harris copies are inferior and will let you down when you need it most.