You need to fine tune it to your gun set up.
You can decrease the dwell, but don't go below 8ms unless you have a particularly fast/great solenoid. Even then below 7 is not a good idea. Reduce your dwell but watch your velocity and consistency. If the consistency reduces put the dwell back up.
What solenoid do you have? With what coloured wires?
Whats your debounce? The lower the value the more likely to get 'extra shots'. What revision board do you have? If you have an earlier rev board you can set it to 1ms very easily and get lots of extra love...
You may be able to reduce your BIP value, but it depends on your loader. If you start chopping put it back up. With a fast loader (Halo, Warp or Q) you can set it very low, with every thing else you will need to set it higher to avoid chops.
Bolt delay, MAYBE, and just MAYBE you can reduce this by a ms or two and still get the gun to work well without making 'skipped' shot noises.