The 3" is a scant 34oz. If you handload the .44Mag would offer little, except the super heavyweights. Which most don't use anyway.I would buy one sight unseen if they made a 44 magnum just like the smith and Wesson model 69 with a 4 or 5 inch barrel and adjustable sights.. That would make a really nice hunting/camping gun for bear country or as a backup deer gun. Honestly for me a gp100 is just a big honking gun that I can't see much use for other than range shooting. No way am I going to lug that around. If it could up the ante into 44 magnum power then it would become interesting. If smith can make the model 69 L frame 44 magnum I really don't see why a gp100 would not be up for it. For a self defense gun I would rather have a charter bulldog just due to size and weight.
I bought my Ruger Blackhawk .44 Special in honor of Elmer Keith. If you don't know who he was you need to find out about him and his relationship to the .44 Special. This should remove all doubt about buying one regardless of manufacturer.