Bright Focus

Sight Apertures

 The Bright image of a large aperture and the sharp Focus of a small aperture,

at the same time … Bright Focus!

 

Installation instructions for BRIGHT FOCUS (Pat. Pending) sight.

 

IMPORTANT. 

  1. Before installing this sight, or doing any work on a rifle, always check to make sure it is unloaded, the magazine is out, and the bolt is locked open.
  2. Do not attempt to make any modifications to your weapon if you are not competent, and comfortable with the task.  If you are unsure, take the weapon to a qualified gunsmith.

 

INCLUDED IN KIT

            Sight aperture, 12-15 shim washers of 0.001” each, threaded sight hood.

 

SIZE EQUIVALENTS

            ORIENTED FOCUS sight apertures are marked with a size.  The marked size is the equivalent diameter (in thousandths) of a round sight aperture with the same total open area, and should give the same image brightness to the shooter.

 

ORIENTED FOCUS SIZE

ROUND APERTURE SIZE OF EQUIVALENT BRIGHTNESS

ACTUAL SIZE OF BRIGHT FOCUS APERTURE

36

0.036”

0.023” x 0.045”

38

0.038”

0.024” x 0.048”

40

0.040”

0.025” x 0.050”

42

0.042”

0.026” x 0.052”

48

0.048”

0.030” x 0.060”

54

0.054”

0.033” x 0.067”

 

Bob Jones Sizes: #1 = 0.042”; #2 = 0.046”; #3 = 0.051”; #4 = 0.055”

 

INSTALLATION

Unscrew the sight hood from your existing sight leaf.  You do not need to disassemble the sight leaf from the rifle.  Sight leaf is shown disassembled only for clarity of the photos.

 

 

Replace the original sight hood with the new hood supplied in this kit.  After the new hood is screwed in and tightened, a threaded section will extend out forward of the sight leaf.  The ORIENTED FOCUS aperture will screw on to this threaded section (note, the aperture screws onto the front of the sight).  For security, I recommend adding a drop of non-permanent thread lock product, like blue loc-tite.

 

 

The BRIGHT FOCUS sight aperture will need to be installed such that the rectangular opening ends up oriented horizontally when the aperture is tightened.  NOTE it is not critical that its orientation be perfect.  Getting it horizontal within 5 or 10 degrees will not degrade performance.  In this orientation, the ‘flat’ of the hexagonal outer shape should be on the top.  Shim washers are included in order to make this adjustment.

Screw on the BRIGHT FOCUS sight aperture finger tight with no shim washers, until the skirt of the aperture seats against the flip sight leaf.

Hold your head back far enough from the aperture that you can clearly see the rectangular shape of the opening in the aperture.  Observe the orientation of the rectangular aperture by imagining a line drawn across the widest dimension of the rectangle as if it were the hour hand of a clock.  In Figure 1, the rectangle points to 2 o’clock and 8 o’clock.

In order to be oriented correctly, the aperture needs to be unscrewed by the equivalent of 5 hours (150 degrees) to get the imaginary line pointed horizontally at 3 o’clock and 9 o’clock .  This adjustment is made by adding 2 shim washers between the aperture and the sight leaf for every ‘hour’ of adjustment required.  (Note, do not overtighten the aperture to adjust the extra hours forward, or you risk damaging it).  In this case, the 5 hour adjustment requires you to add 10 washers.

Reinstall the aperture with the shim washers and snug into place.  The final aperture orientation will be horizontal.  If necessary add/subtract 1 additional washer to see which gets you closest to horizontal.  It is not critical if the opening has a slight tilt, as your eye will not be able to see this small tilt when you are shooting.

 

 

NOTE: The size markings on your aperture might end up being oriented upside down.  If the numbers are upside down, this is also a correct orientation.