They started doing things like shooting electrical lawn darts out of shotguns. The same 1911 that knocked Sylar across the Bennet's kitchen wasn't sufficient to knock Noah off his feet when the Haitian shot him on the bridge.
It's not even blast radius close to correct on firearms. I don't watch "Heroes" for it's firearms, which for the entirety of the first season consisted of a tricked out 1911. I watch it for Hayden Leslie Panettiere, and since the writers seem to have run out of interesting idea, now I watch her play Claire with the mute button set and have just as much enjoyment.