The reason the barrel is "walking" is because of stress. The only way to stop it from walking as it heats up is to send it to be cyrogenically stress relieved. If I may say however,on a big game rifle,all shots should be from cold barrel as when you shoot at game,it'kll be 1st shot from a cold barrel. What you need to do is let the barrel cool at least 5 minutes between shots to keep barrel cool and get realistic group from a cold barrel. It goes without saying that I automatically glass/pillar bed all mypersonal rifles. As to free floating vs forend pressure,you will have to experiment to see which your individual barrel prefers.