From pbnation.com:
The first column is the switches, the f is the time the bolt will stay in the front and the b (dwell) is the time it will stay in the back and the last number is the rate of fire:
Stock Chip:
u= up
d= down
dddd=f=35/1000.b=25/1000=16.7
dddu=f=35/1000,b=35/1000=14.3
ddud=f=35/1000,b=45/1000=12.5
dduu=f=35/1000,b=55/1000=11.1
dudd=f=45/1000,b=25/1000=14.3
dudu=f=45/1000,b=35/1000=12.5
duud=f=45/1000,b=45/1000=11.1
duuu=f=45/1000,b=55/1000=10.0
uddd=f=55/1000,b=25/1000=12.5
uddu=f=55/1000,b=35/1000=11.1
udud=f=55/1000,b=45/1000=10.0
uduu=f=55/1000,b=55/1000=9.1
uudd=f=70/1000,b=25/1000=10.5
uudu=f=70/1000,b=35/1000=9.5
uuud=f=70/1000,b=45/1000=8.7
uuuu=f=70/1000,b=55/1000=8.0