Here is Colossus takin on one of Arcades robots who replicated the Proletarian. This robot was pretty damm strong casue Meggan had to roll with his punch or she would have died and she has pretty good durability.
http://i31.photobucket.com/albums/c379/Doggydogg/Colossusandproletarian.jpg
(He almost took her head off)
http://i31.photobucket.com/albums/c379/Doggydogg/Colossusandproletarian2.jpg
(Arcade must make good robots cause Meggan didn't even know)
http://i31.photobucket.com/albums/c379/Doggydogg/Colossusandproletarian3.jpg
http://i31.photobucket.com/albums/c379/Doggydogg/Colossusandproletarian4.jpg
(Colossus shows up and takes his imposter out)
After Magneto absorbed some of Storms lightning Storm tries to get it back but the suffering Storm still does her best to try and wrest control over the lightning back from Magneto. Colossus gets between the two of them, breaking the circuit while Nightcrawler grabs Storm’s burning form and teleports into the ocean with her. Weakly, Storm thanks him.
More proof that lightning has no effect on Colossus.
Here is Colossus knocking out Warhawk. Warhawks body is organic steel kinda like Colossus' is. After Nightcrawler hurt his fist trying to knock him out Colossus needed only one punch to put him down. Warhawk was even said to be a second rate Colossus.
Heck Warhawk is so tough Wolverines claws bounced off his chest.
http://i31.photobucket.com/albums/c379/Doggydogg/WolverineandWarhawk.jpg
(If he cannot slice Warhawk open he cannot slice Colossus).
http://i31.photobucket.com/albums/c379/Doggydogg/ColossusandWarhawk.jpg
(Goodnight Warhawk).