You can buy one weaker than Rugers from numrich gun parts.
http://www.e-gunparts.com/model.asp?idDept=218 . So far everyone thats used them reports they don't last long.
RW26 made one, but I don't recommed it for the average shooter, as if it isn't fitted correctly, you could poke a hole thru the primer, and get a face or eye full of hot powder, could loose an eye or two.
http://www.perfectunion.com/forums/showthr...=&threadid=4935
Best thing is to send it to Ruger for repair. It will only cost shipping. If this ever happens to me I will ask for a spare bolt assy to be fitted, I believe its $75. Ready to slap in your mini.
BTW were you shooting berdian primed ammo such as Wolf?