01 June 2021

Not Just The Tethers

The Primary Arms PAC5X tether is also the gasket that seals the turret caps.

Like the tether portion, the gasket side spontaneously disintegrated.

Happily, Marv has a pile of air conditioning o-rings and the 9/16" x 3/32" size fit the caps just about right!

 A wee little #61 o-ring serves to hold the tethers onto the screw head too!


Everybody wins!


  1. I'd have thought after watching one set of pseudo-rubber bits disintegrate, you'd go with a small aluminum/SS/brass washer in lieu of that retention-aiding O-ring. If one had a small pin vise, adding a hole in the washer to anchor said retention wires would be one small additional step.
    A good bit of detail grinding could leave the anchor hole as a single ring-shaped lump protruding ever so slightly out from under the screw head, and the rest flush.

    It all depends on how much one really wants to futz with it.

    But you strike me a fairly detail-oriented guy, where toys and such are concerned, else you'd never had added the retention wire to begin with.

    1. If I was confident that pulling that screw wouldn't dump the nitrogen inside the scope, I'd have captured the wire under the screw head.

      I am tempted to drill a hole through the screw head and just doing that.

      Until I cave to temptation, the o-ring will suffice. I don't, generally, take both caps off at the same time so the other cap will keep the removed one local.

    2. Fair enough.

      What about making a C-shaped washer (brass?) with a loophole bump for the wire, slipping it under that screw head, and then capturing it via tightening the screw? Or is even that risking the seal too much as well?

      Whoever designed the caps not to be securely retained and hard-captured from the get-go was a cheapskate and/or lazy cuss. They could have molded or machined a cap retention loop into the body of it just for grins, and skipped using rubber chinesium self-destructing junk, for a 5000% improvement in not losing small, critical, easily-lost caps.

      Somebody probably saved 23¢ on the production costs with that move.

    3. The original tether/seal was a O--O looking deal with one O on the turret to seal the cap and the -- connecting the other O which rode in the groove I've put wire in.

      As "quality" as the tethers were, I am terrified of removing any sort of compression on the gasket by loosening that one screw for better retention of that wire. Eventually I'm going to end up drilling a hole in that screw head and passing the wire through it.

  2. I love it when a plan comes together.


  3. I did an emergency hot-swap on a water heater for a friend of mine. Washer on the outlet side failed. !) cent part, 2 hours of labor.


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