Most I ever tried was 4 plates plus a 25 a side. Thought I was going to die. I believe if my math is correct that it's 455. I know some jackasses that put 5 plates a side on a hammer strength and claim a 500 bench not realizing you don't add 45 for a bar that's not there and it's not the same. I could do 6 plates a side on a hammer but no fucking way could I lift the same weight on a barbell flat bench.