Hello Enfield
Interesting you would mention this about your Ruger. A good friend of mine was visiting the other day, and we were discussing his Older Flat gate Single six revolver. He shared with me that the frame of it has some "Red streaks" through it which he explained to me that they Looked Like Lightning Bolts in nature and he was told by Ruger to send it back and they would re blue it. I guess he elected not to, but asked what would cause it ? Ruger responded telling him, that early on they took the Hot Cast Investment Ruger frames and Placed them in The Silica Sand when they were cooling them prior to Bluing, They somehow Picked up some of the sand and kept it in the steel. Once they were blued these Red streaks appeared. Somehow my Friends Gun made final inspection and got out the door without being noticed. The Silica sand Process was some how changed to eliminate this Red streak issue since... Hammerdown