s&s slip on with no db reducer

Is there a trick to open the end cap to get the db reducer out.

it took us quite an effort to open it..it was a struggle my friend!
patience is all you need!
avoid putting some spray oil on the edges!it doesn't help!
what we did was to put e towel on top of the exhaust avoiding to hurt the exhaust,a plastic thin object in the edge between the plastic cap ant the chrome and with a light hammer start giving some soft hits in order to push it a little out!and that was the trick!!

Thanks for the response and suggestions, I have time and hopefully some patience.