Believe that is a Marlin 101. Contact Numrich at their website- gunpartscorp. They list that firing pin for $5 plus shipping,
High Standard
Marlin model 80
No
45 ACP. Have it checked by a gunsmith before firing.
Try e-gunparts.com
Numrich gun parts has just about everything you need for any modern gun ever made. Check them out.
Try egunparts or S&W
you can find them at gun shows or gun shops used.
The Sears Model 1 may be a Winchester mod 121. L0ok there
I need a diagram of a bentley mod 500 .22 cal firing pin. Can't find one need to get one made
Want ad, gun shop, gun show.
If you don't have a manual, find a gunsmith and ask for help.