Jump to content

Broken Bolt Theory


Recommended Posts

I recently bought a titanium firing pin from Keystone Joe, I thought I would trim the back to see if the inertia firing pin theory worked with the lighter pin.

Well I trimmed too much off and the end of the pin only extends about 1/32" out of the back of the bolt. BUT the gun still fires and the primers have a pretty deep indentation, which brings me to the broken bolt THEORY. Apparently the hammer is hitting the back of the bolt pretty hard, PERHAPS the force of the hammer is contributing to the bolts breaking, the root cause is the hammer spring?

 

All of the springs in the Reising are Wolf

 

Thoughts?

  • Upvote 1
Link to comment
Share on other sites

I think you may be on to something and I'm a little embarrassed that I didn't pick up on it myself. :blush:

When the gun is in battery the bolt is tipped up from the horizontal into the recess in the receiver to create the delayed blowback. That means that the top of the bolt, the strongest portion, is protected. If and this is a very big and quite critical IF the rear face of the bolt is cut perpendicular to the bolt body, then the hammer first impacts the firing pin and drives it forward then impacts the lower rear edge of the rear bolt face. That could ultimately lead to the sorts of bolt failures we are seeing. It would take a lot of cycles for it to happen but at 850 RPM the cycles can add up pretty quickly.

 

I don't have either of my bolts here to measure so if someone else has one handy please measure and let us know. Is the rear face of the bolt perpendicular to the bolt body or is it very slightly beveled such that the bottom of the face is further forward than the top?

Link to comment
Share on other sites

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 account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...