Yes there is a very simple trick.
Go to your local Ace Hardware store and get a 40 cent #5 O-ring.
Then if you look at the top surface of the bat connector (carto removed) you will see that there are four slots cut into it.
The more those slots are covered by the O-ring, the stiffer the draw will be. Just move the O-ring up & down with your thumb nail.
This pic shows it being used with a 510/510 extension, but it is still the same as on the bat connection without an extension.