QUOTE(IrisH - LoonY @ Jan 14 2006, 08:48 PM)

Which octave? Low B - C shouldn't be a problem, high B - C shouldn't be a problem either, nor should middle B - C given you use the right keys.
Use the wrong keys and it's not B to C...
Ben, there shouldn't be a problem going between the two, unless there's a problem with your instrument. Do you have the same problem either up or down a 12th, e.g. going from low E to F, as this would suggest there's perhaps a wayward spring or screw rather than a problem with you. Unless of course it's very top B to very top C (three octaves above middle C), in which case all bets are off!
Anakrron, it's just practice I'm afraid. Try building up to it slowly, don't create any psychological barriers for yourself, and make sure you have plenty of air support.