Any idea how to stop the stock pin from backing out of the right side threaded collar?

When firing, the stock pin slowly backs out of the threaded collar on the right side of the underfolding stock.

I've tried staking it and also tapping it in, but its just loose in the hole. I can pull it all the way out w/ my fingers.

Is there a "jerry rigged" solution that I'm not thinking of? (Find a cotter pin that fits and bend ends or coat hanger etc?)

Thanks,

If you don't plan on taking it apart often, try a little JB weld on the end of the pin. Just enough to hold the pin, not to lock up the stock. To remove hit with propane torch and out she goes.

If you're referring to the ring nut, it is supposed to be directional.  If you can push the pin all the way through, it is defective.  The opposing side is supposed to be smaller than the pin diameter.  Then the larger side is staked.  Do you have a picture?