MAGNETIC BORESIGHTER

1 . A rifle boresighter having a front adapted to face a rifle user after said boresighter has been attached to a rifle and a rear adapted to face away from said user after said boresighter has been attached to a rifle, said boresighter comprising:

(a) a post defining a receptacle that retains a magnet;

(b) a tubular housing having a front and a rear coincident to said front and rear of said boresighter and being supported by said post;

(c) a collimating lens supported at said front of said tubular housing, a reticle supported in said tubular housing and a light window in said rear of said tubular housing; and

(d) wherein said tubular housing is supported by said post approximately midway between it front and its rear, thereby providing a balanced load to said magnet.

2 . The boresighter of claim 1 , wherein said magnet has a roughened front surface, to counteract the tendency of the magnet, and therefore, the boresighter to slide downwardly under the force of gravity while the boresighter is in use.

3 . A rifle boresighter, comprising:

(a) a post defining a receptacle, retaining a magnet;

(b) a tubular housing supported by said post;

(c) a collimating lens assembly supported at said front of said tubular housing, a reticle supported in said tubular housing and a light window in the rear of said tubular housing; and

(d) wherein said magnet is roughened to provide frictional support against the front of a rifle barrel.

4 . A boresighter that includes an optical assembly and a magnet for attachment to the end of a rifle barrel, said optical assembly connected to said magnet by a bridge, and wherein said magnet has a vertical extent of less than 40 mm, thereby reducing the expense of producing said boresighter while accommodating most rifle and scope assembly geometries.

5 . The boresighter of claim 4 , wherein said magnet has a vertical extent of less than 35 mm.

6 . The boresighter of claim 4 , wherein said magnet has a vertical extent of less than 30 mm.

7 . The boresighter of claim 4 , wherein said magnet has a vertical extent of less than 27 mm.

8 . The boresighter of claim 4 , wherein said magnet is elliptical, thereby providing sufficient greater width in the vertical middle, to accommodate a rifle barrel.

9 . The boresighter of claim 8 , wherein said magnet is round.

10 . The boresighter of claim 4 having a round optical assembly attached and supported by a post attached to said magnet, sound round optical assembly having a round collimating lens at the front of said optical assembly and wherein said collimating lens has a diameter of less than 40 mm, reducing scope expense.

11 . The boresighter of claim 10 wherein said collimating lens has a diameter of less than 35 mm.

12 . The boresighter of claim 10 wherein said collimating lens has a diameter of less than 30 mm.

13 . The boresighter of claim 10 , wherein said collimating lens has a diameter of less than 28 mm.

14 . The boresighter of claim 10 , wherein said post has a length, such that the boresighter and said optical assembly are separated, at closest points, by between 12 and 20 mm.

15 . A boresighter that includes an optical assembly, including a collimating lens, and a magnet for attachment to the end of a rifle barrel, said optical assembly connected to said magnet by a bridge, and wherein said collimating lens has a diameter of less than 35 mm, thereby reducing the expense of producing said boresighter while accommodating most rifle and scope assembly geometries.