Use a piano dolly. I have moved several 800 lb safes easily with one other person. Most rental places have them. Looks like this-
http://www.taylorrentaltrumbull.com...al-equipment/moving-products/piano-dolly.html
You should be able to move a 400 pounder by yourself pretty easy unless there are steps involved.
http://www.taylorrentaltrumbull.com...al-equipment/moving-products/piano-dolly.html
You should be able to move a 400 pounder by yourself pretty easy unless there are steps involved.