I did some hunting today to find some mufflers with the round ends and drew a blank everywhere I went so I thought I would have a try at making some.
I found some 40mm thick plate and welded a locating piece of steel in the centre and used for the chuck to hold on to. I machined it to the shape I wanted and that is my top part of the press tool. the bottom part was obviously a female part. I just roughly put them in the press with some 1.2 steel that I cut in a bit of a circle and to my surprise

it actually did a neat compound pressing and to the size I need so now I can go ahead and make the mufflers.
Happy Chappy