There have been many ingenious methods devised throughout the years for carrying bedrolls with rucksacks. Today we discuss a method I found in an old camping book from 1950; The Horseshoe Rig. This is an easy way to configure by just laying your rolled up blanket over or under the rucks top flap and tying the rest of the blanket down each side, thus forming the Horseshoe shape. This rig is extremely easy to setup, furthermore it eliminates any swaying or bouncing of your bedroll whilst hiking, which is common on other setups, giving you a more stable carry on your back.
Give it a shot and see if The Horseshoe Rig improves your rucks stability too.