Sling gets detected as not having ammo. If you're desperate to level ranged "right" now, then you just have to disable the shutdown response to no ammo on setup, and it goes merrily along.
This should be like line 1012 or something like that in the setup procedure. Just get rid of or replace the LogoutSeq line, and it'll start slinging.
Code:
if (ammo < 200) then
LogoutSeq('Low Ammo');
end;
e.g.
Code:
if (ammo < 200) then
Writeln('Sling NO NEED AMMO');
end;
~15k/hr slinging happily on an alt. 1-66 so far