It's because of a poor bipod... Harris bipods are garbage mate... Why spend big money on a long range precision rifle, top it with a great scope like a NF or S&B and then ruin the whole package with a flimsy, toy like bipod that doesn't provide adequate stability... So many people on this site don't see the value in a decent bipod...
Perhaps you are starting to see the light?
A quality properly setup bipod will not bounce, allows better spotting of your impacts, caters for a ideal shooting position and provides a very stable platform. The types of feet are important, the raptor feet on mine don't move in the dirt no matter how many shots I fire but obviously won't do you any good shooting off a hood of a truck...
The balance is very important aswell, a quality bipod will provide a wide stance for stability and the point where it attaches to your foreend is very important to get the balance right. If it's attached too far forward or rearward, the rifle can move in wild movements under recoil which can make spootig shots difficult and cause poor accuracy also. Probably deserves a new thread on this point alone...