What has happened here?
My Stainless Steel Single Six has suddenly tied up and will not cock and rotate the cylinder. Pull the cylinder out and it will cock just fine.
Disassembly reveals a lose piece that looks like a .100" drill rod about a quarter of an inch long that appears to be fractured off on one end.
What has happened and where is this piece from?
Thanks
Byron
Spring plunger at the end of your base pin missing?
If so, the transfer bar is hitting the bottom of the firing pin and locking up the gun.
That or the thingama-springima bobber rod on your hammer (the one that pushes the bolt down to unlock and let the cylinder rotate) broke off. That sounds more likely.
"thingama-springima bobber rod"
AKA the hammer plunger.
I was drawing a blank. 
Spring plunger at the end of your base pin missing?
by Slow Hand 
, Indiana, Sunday, March 30, 2014, 15:09 (3834 days ago) @ cas
If you point it straight up and the hammer will cock, I'd say it's the plunger from the end of the base pin. If not, I'm not much help...
I`ll tell you
by Fivegunner , LOWELL Mi., Sunday, March 30, 2014, 16:47 (3834 days ago) @ Byron
Byron it`s a part that is easy to replace it sit`s in the hammer , it is a pice of drill rod that gives a kick to the locking bolt, you can make one yourself or buy one from Ruger. it`s held in the hammer with a cross pin . a very easy fix.