I've the same question too, some English speakers do not pronounce the letter T when it comes at the end of the word like: not, that, but.....they pronounce it nearly as / /bʌə/ if i am not wrong.Is it right?
Thank you in advance.
So, you said that is more like a glottal stop, I've heard the pronunciation of it in Wikipedia, but it sounds strange to me.
Glottal stop - Wikipedia, the free encyclopedia
Thank you again.