Just for your info..whilst on holiday I bought a 'Posh' snuff bullet. This is a stainless steel afair with a single screw holding the bottom on. After two days of ordinary use, the female part of the assembly had de-threaded making it un-useable. I emphasise that I didn't do anything to make this happen and know how to use a screw driver.
I may have got a faulty one and the rest are great but ended up throwing mine away as by the time it broke I was several hundred miles away from the shop and generally couldn't be bothered etc etc.
It seems like a design fault with the metal in the barrel of the unit possibly being of too soft a type, I don't know but I would suggest not buying this article...
I have two of the type you describe for over 6 months and so far no problems. I think your must have been faulty, snuffster. A tip for anyone filling this type of bullet, always temporally replace the screw in order not to get snuff down the screw hole.