In article ,
says...
I'm working on a project and I need some form
of coaxial latch mechanism. I've seen something
with 3 steel balls and a cone and sleeve that
might work, but I don't know what it's proper
name is or where I can find a picture of it.

If it's any help, I think H&K builds a weapon
that latches the bolt with a similar mechanism.

Any help would be appreciated.



Ball lock pins/quick release pins use this sort of
mechanism. See McMaster-Carr starting on p. 3088. I think
Carr-Lane, Reid Tool, Jergens, et al, sell this sort of
thing as well.

Ned Simmons