I just picked up my old 1873 Model Maynard and the back half of the firing pin fell out on the floor.  This one is a replacement made for me by a reputable 'smith, but these rifles have a reputation for being rough on firing pins.  I don't dry fire it... I even modified a Pachmayr snap cap to keep in the chamber to protect the pin, but break it did!    The fracture line looks as though it crystallized and it goes straight across under the front of the cross notch that the retaining screw passes through. 

SOOO, I am going to make it myself this time and would like to get some advice on what to use.  I am leaning toward air hardening tool steel, but that's just a "stab in the dark."  Does anyone want to chime in and agree or to suggest something that might work better?  As always, TIA for any help or suggestions. 

Froggie

what about the beryllium/bronze alloy stuff.  supposed to be incredible durable.  seems like I remember a discussion about it some while back

  Over the years I have made numerous firing pins for various SS rifles from Ballard's to Stevens and Remington's from O-1 drill rod. My process has been to turn the pins in the lathe and perform any cuts required for retainer screws or pins. Then polish to remove any machine marks. Heat to cherry red with a propane torch and quench in 30 weight motor oil. Carefully remove all scale (I use glass beads) and then smoke the pin with a candle. To temper I use my lead pot set to 650 degrees and drop the smoked pin into the molten lead and leave it there for 30 minutes. The soot from the candle will prevent the lead from sticking to the firing pin. Remove from the lead pot allow to cool and wipe any remaining lead off. Install in the breech block and double check for free movement and you should be ready to head to the range. I have had two out of dozens made this way fail, so it is not perfect but but has kept many rifles going over the years.

SSS

I use spring steel out of junk cars. The springs that are used in the trunk lid come in a lot of different sizes and work good for firing pins and screws. No heat treat after as they are already just about right. They can be cut with a file or hacksaw but still hard enough to hold up to the hammer strike without mushrooming. Drill rod is to hard after heat treat and can break easy.
Check the fit of the pin, if it is to sloppy it can break. If the hole for the pin is worn crooked the pin can break. You may need to bore the hole out to make it strait and lined up with the smaller diameter part of the hole. The hole could also be bushed to take up for ware.

I remember reading about S-7 steel being used for firing pins. I have made a couple from drill rod and grade 5 heat treated bolts. Just a suggestion. Frank

Charlie
What are the dimentions of this pin?
Tom

Respectable stuff:
17-4 Precipitation Hardening also known as Type 630 is a chromium-copper precipitation hardening stainless steel used for applications requiring height strength and a moderate level of corrosion resistance. High strength is maintained to approximately 600 degrees Fahrenheit (316 degrees Celsius).

General Properties

Alloy 17-4 PH is a precipitation hardening martensitic stainless steel with Cu and Nb/Cb additions. The grade combines high strength, hardness (up to 572°F / 300°C), and corrosion resistance.

Mechanical properties can be optimized with heat treatment. Very high yield strength up to 1100-1300 MPa (160-190 ksi) can be achieved.

The grade should not be used at temperatures above 572°F (300°C) or at very low temperatures. It has adequate resistance to atmospheric corrosion or in diluted acids or salts where its corrosion resistance is equivalent to Alloy 304 or 430.
( from (You need to Login or Register to view media files and links) )

Heat Treatment
CONDITION A--Soak at 1900 F (1038 C) for 30 minutes and cool below 60 F (16 C) for complete martensite transformation. CONDITION H 950- Treat Condition A material at 900 F(482 C) for 1 hour, air cool.. CONDITION H925, H1025, H1075, H1100, H1150- Soak solution treated material for 4 hours at specified temperature, air cool, CONDITION H1150M- Soak solution treated material at 1400 F (760 C) for 2 hours, air cool, then re-heat to 1150 F (620 C) for 4 hours and air cool.
 
Forging
Soak for 1 hour at 2150 F (1177 C) prior to forging. Do not work below 1850 F (1010 C). Post-work solution treatment is required prior to final hardening.
 
Hot Working
17-4 PH can be easily hot worked using most of the common processes. It is suggested that material be solution treated at 1900 F(1038 C) then formed during cooling while the material is still austenitic. Post-work solution treatment is required prior to final hardening.
 
Cold Working
Despite its high initial yield strength, 17-4 can be cold worked successfully by most common methods.
 
Annealing
1900 F (1038 C), hold for 1/2 hour, rapid cool.
 
Hardening
This alloy has good ductility and may be readily formed by all conventional methods. Because the alloy is stronger than regular steel it requires more powerful equipment to accomplish forming. Heavy-duty lubricants should be used during cold forming.
( (You need to Login or Register to view media files and links) )