Use a Marlin 57 firing pin. It's the same rifle, just re-branded for Sears.
There were two types of firing pin used on that model. Would need to see the bolt, but we have the pin. gunshop@nctv.com
Numrich Arms
Believe that is a Marlin 101. Contact Numrich at their website- gunpartscorp. They list that firing pin for $5 plus shipping,
You can find a replacement firing pin for a Stevens model 87D 22 cal rifle at a gun dealership. You can also find it by contacting the manufacturer.
gunpartscorp website has a cross reference to find the originial make and model, and usually his firing pins.
No
The Ted Williams model 100 was a Winchester model 1894 rifle.Use this model to order a new firing pin.
Best left to a gunsmith
Your rifle is a Marlin 25M. You can check with Marlin Customer Service, expect price to be AROUND $25 plus shipping.
www.leesgunparts.com I have new firing pins for that model. sales@countrygunsmith.net
gun shop, e-gunparts.com, gun shop
Numrich eparts