A Simple Bipod
Based on your typical shooting posture, determine the height at which you want the rifle supported. Cut two pieces of wood 50 percent longer than this distance. The thickness of wood used is not critical, and you can use anything available. Bipods built out of 1 inch by 2 inch wood are more than sturdy enough to hold a rifle.
Drill holes in each piece of wood and use a bolt and wing nut to secure the two pieces of wood together. Make this connection at a point 20 percent longer than the desired support height. For example, for a five-foot support, use two seven-foot pieces of wood, and drill the holes at the six-foot mark.
At some point below the bolt, secure a strap between the two pieces of wood. This can be nylon webbing, velcro or even string. Set the length of the strap so that the bottom of the tripod forms an equilateral triangle with the ground. Rest your rifle between the two pieces of wood.
If you drill several pairs of holes, the bipod can be adjusted to many different heights.
If desired, the wooden posts can be padded to reduce the chance of scratching your weapon.