fartsalot Posted December 9, 2023 Report Share Posted December 9, 2023 When making the firing pin modification to make it a inertia pin, What over all length to I need to use. I read up on the mod but no length has been given, just keep the pin recessed in the bolt face when the pin base is even with the bolt base.. How much should the recess be? Link to comment Share on other sites More sharing options...
StrangeRanger Posted December 9, 2023 Report Share Posted December 9, 2023 As close to zero as possible Link to comment Share on other sites More sharing options...
fartsalot Posted December 9, 2023 Author Report Share Posted December 9, 2023 10 hours ago, StrangeRanger said: As close to zero as possible Ok I got it and It takes a good strong firing pin spring such as wolf spring ?? Right? Link to comment Share on other sites More sharing options...
Ryo Posted January 10 Report Share Posted January 10 I used the original spring. I am also using the "original" firing pin. Worked out fine Make the pin not stick out at all or recessed a bit. The hammer would throw that forward hard. Link to comment Share on other sites More sharing options...
Frank Iannamico Posted April 6 Report Share Posted April 6 Has anyone successfully modified a Keystone titanium firing pin into an inertia pin? I often get several light-firing pin hits that won't fire the round. My thoughts are that the titanium pins are too light in weight to function as an inertia firing pin? http://www.machinegunboards.com/forums/ind...?showtopic=8854 Link to comment Share on other sites More sharing options...
fartsalot Posted April 7 Author Report Share Posted April 7 I have a titanium pin that has been shortened and every once in a while I have a light primer strike. I think I got a little aggressive and removed too much metal thus making it lighter. I milled the pin down to 3,970. Over all I have no issue with the seldom light strikes. I keep the channel the pin rides in super clean to eliminate any movement from drag caused by powder residur. Link to comment Share on other sites More sharing options...
Ryo Posted April 7 Report Share Posted April 7 I don't think it being lighter would be your issue. It would be more of the contact/transfer of energy from the hammer to the pin to the primer. I remember having to modify my pin (the one that came with the Reising) so it could move further back so the hammer could contact it better. With the mod the pin only protruded backwards only a tiny bit which was not enough. I had to take a round file and open up that channel on the side, allowing it to move further back to allow the hammer to contact. Also I would check to see how far the pin protrude to see if it would have good contact with the primer. Link to comment Share on other sites More sharing options...
fartsalot Posted April 8 Author Report Share Posted April 8 "channel" Are you referring to the flat spot on the pin? If not I don't know what you mean channel Link to comment Share on other sites More sharing options...
Ryo Posted April 8 Report Share Posted April 8 Yes the flat spot. That limits the movement. Don't modify it if it has full movement in exposing the rear of the pin to the hammer. That flat spot limits how far back that pin can go. Link to comment Share on other sites More sharing options...
fartsalot Posted April 9 Author Report Share Posted April 9 OK I will check that out, but when the pin is modified that part that hits the hammer is removed to make it a inertia pin. Looks like there need to be a balance between the pin on the primer end protruding out too far and the other end not exposing itself enuf for the hammer to give it a good whak to set off the primer. I have a light strike about once every 400 rounds. I shoot her often since I can use my back yard (lucky me) but it keeps me constantly reloading LOL. Link to comment Share on other sites More sharing options...
StrangeRanger Posted April 9 Report Share Posted April 9 (edited) FWIW the firing pin protrusion spec for a "28 or M1 TSMG is .044-.050". With a Reising obviously YMMV but probably not by very much Edited April 9 by StrangeRanger Link to comment Share on other sites More sharing options...
Frank Iannamico Posted Tuesday at 08:32 PM Report Share Posted Tuesday at 08:32 PM On 4/6/2024 at 10:34 AM, Frank Iannamico said: Has anyone successfully modified a Keystone titanium firing pin into an inertia pin? I often get several light-firing pin hits that won't fire the round. My thoughts are that the titanium pins are too light in weight to function as an inertia firing pin? http://www.machinegunboards.com/forums/ind...?showtopic=8854 Update I modified the channel on the pin so it protrudes out the back a little further, the gun ran fine today. No more light primer hits. Link to comment Share on other sites More sharing options...
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