That type of jack is only used in homemade or small-batch electronics with panel-mounted jacks. No computer I've ever seen Apple make (nor any other mass-produced product, for that matter) has used such a thing.
All the aluminum machines use apparently custom jacks that mate with precision made holes in the housing.
If the jack is loose, I'd look at two things: 1. try different plugs to see whether it's the jack or the plug. 2. If it's the jack, the only way to fix it is to replace the logic board, which is in no way economical. Instead, either use the front-panel headphone jack instead, or connect an AV receiver using the optical output, or use a USB audio "card" to give you a fresh jack.