This mod of the end of the mufflers (silencers) is referred to as a "bafflectomy."
It's fairly easy to do on the earlier models like yours, but a little harder on later ones.
It has been discussed at length here some time ago, but I don't know if there is a tutorial on it or not.
Do a search here on the site using the word "bafflectomy" and I'm sure you will find plenty of threads that discuss the process.