Well there are a few things that could be giving you the low trajectory.
First there's your swing. without seeing it i can't really tell you if it's a factor or not, but some swings naturally yield a low ball flight, especially if you tend to hit more down on the ball with the driver instead of a sweep/upswing.
Second. Loft. obviously if you're using a 12 degree driver it's not an issue. Remember there's Bulge and Roll on the face. That means if you hit the ball lower on the face, you'll have a lower trajectory if you hit it in the middle. Likewise, if you hit the ball higher on the face, you'll have a higher trajectory than middle.
Third. Shaft. Do some perusing in "the wedge guy" area of the site and come across his articles on the shaft as the transmission of the golf swing. When you swing, the shaft has to impart your power and energy onto the ball. If the shaft is not unloading at the right time or in the right way, your trajectory will be off. There are mid kick, high kick and low kick shafts available. Trajectory is opposite the "kick" - i.e. high kick shafts have a lower trajectory, and Low kick have higher. Take stock of what you have on the driver and see if you can have a conversation with your local pro to decide what's right for you. If you're playing a 12 degree driver and hitting it over 300 though, i wouldn't be messing with it too much, nomatter how high or low it goes. I'd take that any day.
Last edited by birdieXris on Mon Mar 07, 2011 3:15 pm; edited 1 time in total