03 rear sight components image

[Parashooter]

1903rear.jpg
Image shows some critical areas of the model 1905 rear sight found on most M1903 and M1903A1 rifles.

Stud (a) fits in the hole (A),
Rear lip (b) mates with the rear radius (B),
Windage worm threads (c) work on the windage gear sector (C),
Tension of the worm spring (d) serves to suppress side-to-side play of the movable base.
Spring at (e) holds the rear sight movable base down flat on the surface to suppress side-to-side wobble of the leaf when raised.

[butlersrangers]

Nice tutorial "Parashooter", thanks!

[John Beard]

Seasons' Greetings!

The problem with your tutorial is that it fails to address and accommodate the engineering design of the rear sight. I regularly have to repair rear sights at the CMP from mis-trained military armorers who have followed your procedure. I have enhanced and expanded my vocabulary from the unkind things I have called them.

Happy New Year!

J.B.

[Parashooter]

Mr. Beard, I would sincerely appreciate any and all recommendations from you so I might edit my post to incorporate a better understanding and better procedures.

I have described what worked well for me on about a half-dozen of these sights, based only on my estimation of how the elements should work together, and would very much like to learn and share a better way.

[John Beard]

The M1903 rear sight is based on the design of two springs: (1) one at d, and (2) one at e. The spring at e, as you correctly noted, holds the rear sight movable base down flat on the surface to suppress side-to-side wobble of the leaf when raised. The spring at d provides compression for the two cams at the ends of the windage screw. The cams at the ends of the windage screw work against chamfers at each side of the fixed base beneath e. The spring-compressed cams push the rear sight movable base back against the stud at a and suppress side-to-side play of the movable base, to include any play from worn or poorly-fitting screw threads. The bolster at b should be loose-fitting and merely provides damage suppression for the sight when the leaf is raised and a marker for the windage scale.

The sight is correctly adjusted for windage like tuning a guitar string. Windage is correctly adjusted by turning the windage knob counterclockwise to the desired setting. If windage is over-corrected, then turn the windage knob clockwise some distance, then counterclockwise again to the desired setting.

I commend your good and well-labelled picture!

J.B.

p.s.

When the rear sight is working correctly, you should be able to push the movable base counterclockwise slightly against the spring compression at d, and have it return when released.

[Parashooter]

Thank you, sir. I have edited the post to remove suggestions for "tweaking" the sight, leaving only what I hope to be useful description.

[PWC]

Lyman - This should be a sticky, or part of the 03 tech knowledge.