I have a Winchester M-94, s/n 4.5 million in for repair. Broken top tang. Is this receiver material weldable or not? It looks like fine grain cast but not sure. I know I can silver braze it but would rather weld it if possible.

Assuming this source is correct:

...they changed to a sintered metal casting process using an alloy that included graphite, nickel or chromium (actual recipes are not known, nor available from any source that I could find).

http://tincanbandit.blogspot.com/2014/02/winchester-model-94-rifles.html

Castings can generally be welded, provided you know what alloy they are made from and use a welding and pre/post heat treat process appropriate for that alloy.

Would be worth contacting Winchester, hopefully they can/will tell you the alloy they used so you can find an appropriate welding process.

Could this be the final word?

"During the early 1960's, the Winchester Model 94 was redesigned to accommodate a more economical method of production. The re-engineered receivers were machined from a graphitic steel casting." Sintered isn't mentioned.

From here...

http://www.du-lite.com/dulite_94_win_oxide.html