http://mysite.elixirlabs.com/index.p...2665&page=1624
This chart might help you out some. Granted it is from Corbon but it will give you a baseline of safe-and-sane factory loads.
Please be advised that you can handload .44 magnums to a max load and achieve above what are listed but only do so in a safe manner prescribed by the loading manuals published by reputable sources.
My father used to hunt with his .44 magnum, he loaded his own with the maximum allowable powder and I believe a 240 grain bullet as well. I am unsure of the load specs because he hasn't reloaded in a long while now.
If you want further distance perhaps use a 180 grain bullet instead of 240. Available in Jacketed Hollow Point from Hornady, they are great bullets and will give you a little more velocity and 'distance'.
Hope that helps, I'm sure others will chime in.