I have a 1/9 twist M-4 profile barrel made by adrenaline arms to get rid of. It is brand new, no front sight base but comes with barrel nut. It is M-4 profile, 14.5 long and threaded, but does not have the step down for the 203. $190 shipped
If I am understanding you correctly this barrel is basicly a pencil thickness under the handguards and a heavy profile in front of the sight base? Kind of lick a 16 inch A2 goverment profile barrel. Pictures would be nice if available. Thanks.