Friday, February 19, 2021

Penetrating Oil

I have a rifle with a Bushnell 3x9-32mm Sportview scope.  Whoever installed it, put in the scope upside down, so elevation adjustment was not going to happen.  It seemed to be properly zeroed the last time I shot it in the 20th century.   But a simple set of crosshairs is not very useful for long range shooting.  Anyway, I could not remove it because the 8 screws holding the top ring were refusing to move even with my gunsmithing screwdrivers.   (If you do not have these,  you should.  They do not slip and tear up the head, like whatever fool installed this scope with a conventional screwdriver.)

So I bought some penetrating oil, and now the screws just came right out.   They are 6-32, so I will replace them with some SHCS screws, which are a much more certain way to get screws in and out without damage.  The tube is 1" diameter, so I can replace it with a Redfield 4-12x40mm scope with the Accu-Range reticle.

Just to clarify, these are caps, not turrets.  Being on the underside of the scope made adjusting clicks impossible.

UPDATE: I guess word got out about what a bargain the Redfield is; most retailers are showing it no longer available (at least through them).  Amazon shows it at $399!


  1. Some moron didn't locktite the screws, did they? I've fixed more than one with red on the threads. A 'special' (read disposable) screwdriver you heat the tip to near red and stick it in the head of the screw and just hold it there until the screw moves.

    1. soldering iron does the sane thing, only better.

  2. A few years ago I bought an inch pound torque tool for gun work. I've noticed a change in scope mount fasteners to Torx.

  3. Millerized: Torx is a better fastener head, for sure.

    John: That is what I thought at first, but I would not expect penetrating oil to loosen Loctite. The heads were so chewed up that I suspect a gorilla was hired.