Thanks for the reminder on HCl and the alum method gentlemen.
Also had a local gunsmith suggest using a Dremel tool with dentists' burrs.
Got it out and retapped to 4-40.
Mike in BC

On Wed, 09 Apr 2008 10:39:14 -0700, freemab222 wrote:

Taps are steel and are easily dissolved in muriatic acid. Bronze will lose
a little tin at the surface (or zinc if it's really brass), but will not
be etched away by muriatic. Wear gloves and goggles. Carefully add
muriatic acid to the hole. Bubbles of hydrogen gas will form as the tap
dissolves. You needn't dissolve it completely - just enough to allow you
to screw it back out using needlenose or some such tool.
Bruce
NJ