Buffalo Arms sells a nice set of shooting sticks.

The lead sled is a bad idea. IT does not let the rifle recoil naturally. Your rifle will shoot a different POI in the field. Also it is a bad idea to shoot bipods off of a solid bench, and even worse to shoot a bipod off of a truck. If you are using a bipod to sight a rifle in, then you should sight your rifle in using the same conditions as you hunt in.

The reason for the difference is the amount of time the bullet spends in the barrel. The lead sled reduces barrel jump, which as I stated above will chage POI when in a hunting position, unless you hunt with a lead sled. I have heard alot of shooters say how can I increase the velocity of my pistol cartridge, and my bullet impacts lower. This lower impact is due to shorter barrel time. Remember the higher the MV, the less barrel time, therefore less POI change. To really notice the difference try pistol shooting, or big bore shooting. Tom.