I`ll tell you
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. 
Complete thread:
- What has happened here? - 
Byron, 
2014-03-30, 13:17 
- Spring plunger at the end of your base pin missing? - 
cas, 
2014-03-30, 13:35
- "thingama-springima bobber rod" - cas, 2014-03-30, 13:42
 - Spring plunger at the end of your base pin missing? - Slow Hand, 2014-03-30, 15:09
 
 - Is that the spring plunger.... - Glen, 2014-03-30, 16:28
 - I`ll tell you - Fivegunner, 2014-03-30, 16:47
 
 - Spring plunger at the end of your base pin missing? - 
cas, 
2014-03-30, 13:35