dirty said:
In my experience, more open mouthpieces are just not significantly louder on clarinet. What you have should be fine. Maybe try harder reeds and more air? That can give you projection like you wouldn't believe.
Your 5RV Lyre is perfect for what you are using it for. They have ample projection and I have seem many jazz musicians use it.
While many get a wondeful sound out of a B45, they are infamous in the clarinet community as the "band director's suggestion." They naturally produce a shrill less-focused tone that works fine playing Sousa. However, there is a list of very fine players using the B45 with a wonderful huge, dark, room-filling sound. It takes effort though, as it's not the kind of sound it naturally produces.
On saxophone I use tips on the large side to gain projection; on clarinet I use smaller tips to gain projection. In my experience, it takes significantly more projection to cut through a full orchestra than it does in a jazz band. Of course, being heard in a pit situation is simply not an issue since everything has to be so quiet...unless there's an air support issue.
Doublers get real caught up in the open clarinet mp thing because they think they can turn it into a sax.
When your looking at the worth of a clarinet mouthpiece you need to consider two things: It's resistance and it's response. If those two attributes feel comfortable to you, than with the correct air suppport, projection will not be a problem.
Your 5RV Lyre is known for having a comfortable resistance/response for most people. Is it comfortable for you? If so, another mouthpiece will simply be different...not more projecting.