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Firing pin

Twdmar

Plastic
Joined
Nov 8, 2020
I am, at some point, going to attempt to make a firing pin for a tubb 2000 rifle. The original firing pins were made of s7 tool steel. Is there a comparable steel with a simpler heat treatment scheme?
 
I will have to look into. This thing is pretty different than most pins. It's hollow with the firing pin spring inside of the pin. It also has 2 cocking cams and sear at the back end as well.
 
What makes you think that you know more than McMillan as to what material is required. I am familiar with the Tubb 2000 and there is a good reason why they use the material that they do. A word of warning, if you experience a case failure induced by your firing pin you are in for a world of pain. The Tubb has no gas venting ports in case of a failure and expects to vent through the mag well which is aluminium and filled with a magazine, go figure. I have personally witnessed an event where the mag well cracked in four places and some parts ended up in the shooters face, various parts are still missing in action. This is not an isolated case, do a search and you will find more instances.
 
What makes you think that you know more than McMillan as to what material is required. I am familiar with the Tubb 2000 and there is a good reason why they use the material that they do. A word of warning, if you experience a case failure induced by your firing pin you are in for a world of pain. The Tubb has no gas venting ports in case of a failure and expects to vent through the mag well which is aluminium and filled with a magazine, go figure. I have personally witnessed an event where the mag well cracked in four places and some parts ended up in the shooters face, various parts are still missing in action. This is not an isolated case, do a search and you will find more instances.
Good for you
 
You need a good selection of old Unbrako bolts ......they are metric 12.9 grade,and machine easily ,and quite likely can be spot heat treated ...........Ive made pins that are hit by old style mule ear hammers ,and they just do not deform .
 
You need a good selection of old Unbrako bolts ......they are metric 12.9 grade,and machine easily ,and quite likely can be spot heat treated ...........Ive made pins that are hit by old style mule ear hammers ,and they just do not deform .
I would need to heat treat 4 different spots. 1 cocking cam, 1 cocking cam that is also the sear surface, the slot for the spring retaining pin and the tip. If nothing else, they sound they would make a great test piece.
It would be a lot easier than the procedure for s7. I'd like to use the s7 and am hoping to find a heat treater that could take the project on. I'm not sure my own heat treat oven would work so well though because of how involved s7's heat treat is.
 
instead of s7, what about 4130 or stressproof and having it Nitrided?
I was thinking pretty much that as a possibility with 4130 prehard, hard enough and tough enough and with good wear resistance with nitride. Then i might not have to worry as much about heat distortion that way as well.
One of the air hardening steels with a simpler heat treat regimen like a2 might make a decent substitute
 
What's the problem with S7 heat treatment? I've done it and it's simple as dirt.
I don't consider myself much of a heat treater so it looks a little intimidating. Most of my experience is with o-1. Is it doable with a simple heat treat oven? I don't have vacuum to it.
 
Typically ,the part is coated in a melted glass to protect it from decarb .....such as borax ......spot heated and quenched ..Done professionally ....IMHE ......,a simple inert atmosphere heat treat on one part is $100 .....and if its identified as a gun part ,its then "No dice,wont touch it"............and that pricing would be 10 years ago
 








 
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