The long and the short of it
I'm thinking and planning for my week long trip around Merasheen Island in August. One of the things I wanted to address was freeing up more cargo space. I use a MEC WinterHawk sleeping bag that comes with its own stuff sack(on the right). I felt there was about 20% more compression possible so I invested in an Outdoor Research compression bag (on the left).
I was anxious to test the compression bag right away so I started stuffing. To my chagrin, it went in alright but I didn't get the expected space saving. In compressing the bag it went crooked and I lost a lot of further compression. I figured the sleeping bag wasn't right to the bottom of the longish bag.
I put on my thinking cap. I stuffed it first into its own stuff sack and then tried to get it into the compression bag. The stuff sack was wider than the compression bag so it wouldn't go in.
Necessity being the mother of invention I found the right solution. I folded down the compression bag outside over itself until it was about the same length as the stuff sack and then put the empty stuff sack into the compression bag. I stuffed the sleeping bag into the stuff sack and cinched up the cord to close it.
Then I brought the slipped down sides of the compression bag back up, folded the closure and leaned on the compression bag to get my anticipated saving of space. It worked like a charm.
Now all I have to do is decide what else I can take in the freed up space.