Hi i bourght my first secondhand trumpet with a 7c mouthpiece made by elrham.I am a first time player and understand that everyones lips are diffrent sizes. And would like to know if any one hase a gide or rule of thumb to slecting the size of mouthpiece needed.I also understand that a 7c is a good alround mouthpiece to start with.Any help would be helpful

7C is a good starter mouthpiece. Stick with it for an year or 2 to get the basics mechanics of playing under your belt and only when you decide if you want to do something more specific you may need a teacher to help you pick up another mouthpiece if needed. However, I am not suggesting that till then it would be a good idea to learn the trumpet on your own...

a 7C is what everyone (usually) starts out with --- it will work fine --- don't get caught up in mpc and pro trumpets --- you will know in 2 or so years if you want a change --- otherwise the 7C is just fine. practice, practice, practice will make the 7C comparable to any other mpc (in range and sound)

yes, its what most people start out on.