Porrick, I've been on the practice chanter for about a year, and I have found the same thing as you. I've just gotten real pipes, and it's the same issue. For me, the lips are the limiting factor. I practice for as long as I can, and by the end I'm blowing more air out the sides than down the chanter/blowpipe. All I can say from my limited experience is that if you just keep at it, gradually your embouchure gets stronger and stronger. I sometimes approach it like weight training: practice until your lips fail, take a 30 or 60 second break, then go at it again; practice, fail, then break, etc. Good luck!