Firefox has it built in, no redirect necessary, and you don't even need the bang: https://support.mozilla.org/en-US/kb/how-search-from-address-bar?redirectlocal

Firefox has it built in, no redirect necessary, and you don't even need the bang: https://support.mozilla.org/en-US/kb/how-search-from-address-bar?redirectlocale=en-US&redirectslug=Smart+keywords https://support.mozilla.org/en-US/kb/how-search-from-address...