Daprezzz

I have a dewalt 20v pex expander tool that came with 1/2”, 3/4”, and 1” expander heads. I couldn’t find a dewalt 1 1/4” head so I bought a Milwaukee one and when I try to use it, it slips out of the pex pipe and even makes a deep groove in the pex pipe that leaks later. Did I get a d fective Milwaukee head or are they just not compatible? Do I have to buy a Milwaukee kit to be able to run larger pex sizes? I would rather keep it all dewalt because my tools are all dewalt and I like it that way ( only 1 type of battery to charge and I am happy with the quality. Is there a dewalt option?