When we migrate to rollforheresy - since this has become so popular a topic - I'll re-post it there as a PDF you can give your players!

Stay GAMING

Morbid

Alternatively:

Semi-auto applies a -10 penalty to the attack roll, but adds [DoS multiplier] damage to the attack

Full auto applies a -20 penalty to the attack roll, but adds 1 to the DoS modifier

Sorry if you've thought of that already, I haven't read the whole thread

Here's an updated TABLE

It now includes the Vanilla info for Damage & Range...