I was recently given a box of Grolsch bottles by a friend who knows I homebrew. I keg but figure I can use these as tiny growlers and fill up a 6 pack or so to take places. Can I expect these to have more longevity than a growler would if I just fill them like I would a growler, or would I need a beer gun of sorts for that to be true? How long would you expect them to stay carbonated? I'm hoping oxidation wouldn't be much of an issue as I'd be filling them from the bottom and leaving little to no headspace, but if I'm wrong I'm all ears.