I carried (and still have somewhere) a USGI Stainless steel canteen for years and years. I really liked it better than the newer plastics, altho I have some of them too. I have never had a problem with my plastics leaking. The SS would leak on occasion, I would just cut a new cork "gasket" for the cap and no more leaks. Neat thing about the SS canteen is that, if you remove the cap, you can heat water in it...