Frank Iannamico Posted November 25, 2019 Report Share Posted November 25, 2019 Well, I finally got out and tested the new-made Indianapolis bolt, the bolt fit and functioned perfectly!HOWEVER, the redesigned Keystone titanium firing pin broke after 400 rounds, looks like there still is a problem to solve. BTW the firing pin was shortened to an inertia-type as per the instructions on this site.http://www.machinegunboards.com/forums/index.php?showtopic=8854 I'll post some pictures later. Link to comment Share on other sites More sharing options...
Frank Iannamico Posted December 3, 2019 Author Report Share Posted December 3, 2019 pictures added The "in the white" bolt is a NOS H&R Reising bolt. The darker one is the new Indianapolis Ordnance bolt.The key to the new bolt is a radius cut where the action bar fits. This is a common area of cracking on original bolts due to the sharp corner. The standard action bar functioned, no alterations needed. Also shown is Keystone's titanium firing pin. This one lasted 410 rounds. IMHO this is still a problem area. Any engineers out there with a solution? Link to comment Share on other sites More sharing options...
jim c 351 Posted December 4, 2019 Report Share Posted December 4, 2019 Frank,Do you think it advisable to file a small radius on the standard Reising to prevent cracking???Jim C 2 Link to comment Share on other sites More sharing options...
jim c 351 Posted December 4, 2019 Report Share Posted December 4, 2019 Frank,Have you looked into the possibility of modifying a firing pin from some other gun, one that doesn't have a bad rep, into a Reising pin.Perhaps a BAR pin?? Remington 870 ?? Jim C Link to comment Share on other sites More sharing options...
StrangeRanger Posted December 4, 2019 Report Share Posted December 4, 2019 That deformity in the broken FP's shaft at about 1/4 length is very interesting. It would take one hell of a lot of force to do that Link to comment Share on other sites More sharing options...
Orion Posted December 4, 2019 Report Share Posted December 4, 2019 The firing pin could have the same issue as the original bolt, not enough radius in the area where the smaller diameter meets angle of the larger diameter. Link to comment Share on other sites More sharing options...
StrangeRanger Posted December 4, 2019 Report Share Posted December 4, 2019 it's not the broken firing pin tip that concerns me, there are many possible answers to that riddle and a stress concentration where it necks down is certainly among them. What puzzles me is the deformity in the firing pin shaft about 1/4 of the way back from the tip and a somewhat smaller one about 3/4 of the way back. Both are clearly shown if you look at the shadow line on the picture of the broken pin. The force, whether axial or transverse, that would be required to cause that is massive, orders of magnitude more than could ever be exerted by the hammer. Whatever caused that is what is causing the pin failures Link to comment Share on other sites More sharing options...
Frank Iannamico Posted December 4, 2019 Author Report Share Posted December 4, 2019 it's not the broken firing pin tip that concerns me, there are many possible answers to that riddle and a stress concentration where it necks down is certainly among them. What puzzles me is the deformity in the firing pin shaft about 1/4 of the way back from the tip and a somewhat smaller one about 3/4 of the way back. Both are clearly shown if you look at the shadow line on the picture of the broken pin. The force, whether axial or transverse, that would be required to cause that is massive, orders of magnitude more than could ever be exerted by the hammer. Whatever caused that is what is causing the pin failuresI thought someone would catch that deformity, that is a SNAFU from trying to remove dog hairs from the pin with PhotoShop. The pin is not deformed there. I have a white bulldog that sheds like crazy. I removed the altered photo and replaced it with the original with the dog hair. Link to comment Share on other sites More sharing options...
StrangeRanger Posted December 4, 2019 Report Share Posted December 4, 2019 You just saved me from sitting down this evening and calculating the Euler column load that would do that to a firing pin. Link to comment Share on other sites More sharing options...
Frank Iannamico Posted December 10, 2019 Author Report Share Posted December 10, 2019 Frank,Do you think it advisable to file a small radius on the standard Reising to prevent cracking???Jim C I am going to do that to my other spare bolts. Link to comment Share on other sites More sharing options...
Frank Iannamico Posted December 10, 2019 Author Report Share Posted December 10, 2019 Frank,Have you looked into the possibility of modifying a firing pin from some other gun, one that doesn't have a bad rep, into a Reising pin.Perhaps a BAR pin?? Remington 870 ?? Jim CI am going to try that. That was my previous plan, but a friend/C2 mfg. Made me one that "wouldn't break." Well it did break. A BAR firing pin is candidate as well as a M16 pin. Link to comment Share on other sites More sharing options...
skoda Posted December 12, 2019 Report Share Posted December 12, 2019 I took my broken Keystone titanium firing pin and drilled the end out with a 1/16" drill. I then broke the shank off of the drill and brazed it into the firing pin. I then ground the new tip down to the recommended length by Paul F. I still have feeding problems that I need to work on but the firing pin has lasted a lot longer. 1 Link to comment Share on other sites More sharing options...
jim c 351 Posted December 13, 2019 Report Share Posted December 13, 2019 skoda,Great idea.Jim C Link to comment Share on other sites More sharing options...
Frank Iannamico Posted December 13, 2019 Author Report Share Posted December 13, 2019 I took my broken Keystone titanium firing pin and drilled the end out with a 1/16" drill. I then broke the shank off of the drill and brazed it into the firing pin. I then ground the new tip down to the recommended length by Paul F. I still have feeding problems that I need to work on but the firing pin has lasted a lot longer.Drill rod may be too brittle, if it breaks, try the tip from an M16 or BAR firing pin. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now