Makes no sense that the axis is causing the Talon to give a different voltage than the button. If it were an electrical problem, you should see consistent and identical results for axis vs. button.
One problem I've frequently seen is:
Code:
if (js.getRawButton(SHOOTER_BUTTON))
shooter.set(1.0);
System.out.println(shooter.get());
... 200 lines of code later ...
Prints 1.0 but sets to 0.7.
If you're multi-threading, maybe something else in another thread is modifying the shooter?
It just doesn't make sense that the problem is electrical related. If you don't want to post your code, it's fine, but we can at least help you eliminate the possibility of the problem being your code.