The level 10 bolt needs more pressure to push the bolt and fire, even with the same gold bolt spring. That means you need to increase the velocity setting just to get back to the same velocity setting as before. However, the gold spring will usually work in most instances. If you installed a stiffer spring, then the pressure requirement is even greater and almost always requires an increase in the velocity setting just to get the gun to fire. If you turn the velocity up and the gun doesn't fire, then your carrier size is probably too small. That's assuming your gun was working and fired properly with the level 7 bolt.
Except for the Automag in front, its usually the man behind the equipment that counts.