looking for the spring that fits into the thumb latch on the safety for a ruger mark 3. I have the round head pin but I lost the spring. Will a mark 2 spring fit?
I found the parts books for the Mk III and Mk II at the Ruger website.
I think you are speaking of the safety detent spring. If so, they list the safety detent spring as part #A20200 for the Mk II; however, the safety assembly for the Mk II is sold as a complete unit according to the parts booklet.