Found these console commands out. Try it out yourself:
physcannon_maxforce # changes how powerful the gun is
physcannon_maxmass # changes maximum mass you can pull
physcannon_pullforce # changes how fast objects are pulled
physcannon_tracelength # changes how far you can pull things
physcannon_cone # changes the radius in which things can be pulled. You can turn into a human magnet with this
physcannon_maxforce # changes how powerful the gun is
physcannon_maxmass # changes maximum mass you can pull
physcannon_pullforce # changes how fast objects are pulled
physcannon_tracelength # changes how far you can pull things
physcannon_cone # changes the radius in which things can be pulled. You can turn into a human magnet with this