Aligning Scope to bore parallel ??????

[rbertalotto]

How are you folks lining up your scopes to be absolutely certain it is parallel with the bore. I'm using windage adjustable bases. But if I get it windage adjusted at 100 yds, it could be way off left or right at 500 if the scope isn't perfectly parallel to the bore...

Brownells used to sell a 30" x 1" rod just for this, but there was no way to reference it to the bore.

Any ideas?

 

[rbertalotto]

Anyone use one of these

http://www.microlevel.biz/vertical_retical_instrument.html

nstructions for the Vertical Reticle Instrument



Important Safety
Information

Safe handling and use of firearms depends on you.

Always follow the manufacturers safety instructions provided with your firearm. If you do not have this information contact the manufacturer of the firearm and request it.

Always follow established firearm safety rules and practices.

Firearms retailers and shooting ranges can also provide you with or direct you towards information and training about firearm safety and instruction.
The Vertical Reticle Instrument

will help you to position your scope's reticle during the scope mounting procedure so that the vertical crosshair will be aligned precisely with the center of the bore. This alignment is desirable because only when it exists does the vertical crosshair represent the true rise and fall path,trajectory) of your bullet. When this alignment is in error the path of the bullet moves from one side of the crosshair to the other side at the distance it was sighted in.

The Vertical Reticle instrument is simple to use and extremely accurate. It is a precisely machined tool that should be handled and stored with care. Read these instructions carefully and follow them closely when using the Vertical Reticle instrument.

Instructions for use of the
Vertical Reticleâ„¢ instrument




Always be certain the firearm or gun is fully unloaded and the action is open before using the Vertical Reticle instrument. Never under any circumstances load or shoot a firearm with a Vertical Reticle instrument attached to it.





illustration 1
STEP 1
Choose a vertical reference line which may be easily and clearly viewed through your scope. There are a number of possibilities to choose from, a few suggestions are provided below:

Good: The edge of a door or window jamb or vertical lines in wood paneling.

Better: A dark line scribed onto an inside or outside wall using an accurate carpenters level as a guide.

Best: A string under tension from a freely suspended heavy weight.

Avoid: Telephone poles, flag poles, fence posts, etc. are poor choices.

Note: Some scopes will not bring nearby objects into focus which may make it difficult to work indoors. Looking through a window to a vertical reference line outside may be an option.











STEP 2

Stop!!! Before proceeding be sure the firearm is unloaded and the action is open!!!


Cradle the gun securely in sandbags or a gun rest so that the barrel is held in a horizontal,level) position and the vertical reference line chosen in step 1 can be viewed clearly through the scope such as shown in
illustration #1.

Loosen the screws on the scope rings just enough so that the scope may be rotated within the rings with a gentle effort.

Loosen the thumb screw slightly so that the barrel V-block and the scope V-block position setting can be adjusted. Place the Vertical Reticle instrument onto the scope and barrel of the firearm as shown in illustration #2.






illustration 2
Important - Note that the scope and the barrel must each contact both surfaces of each V-block, four contact points in all, during all measurements and observations.

A small rubber band may be looped over the objective end of the scope and the exposed threaded end of the thumb screw to help hold the instrument in place but be certain the four contact points are maintained.

STEP 3
Now slowly tilt the firearm slightly from side to side until the bubble is centered exactly between the calibration marks of the level vial. Then view the vertical reference line you have chosen through the scope. If the vertical crosshair of the reticle is not perfectly parallel with the vertical reference line the scope body must be rotated slightly and these steps repeated again. Repeat as necessary until perfectly parallel lines are achieved as shown in illustration #3.

Before tightening the screws of the scope rings double check your work:



illustration 3
1. The vertical reticle instrument has four points of contact.
2. The bubble is centered exactly between the calibration marks.
3. The vertical crosshair is exactly parallel to the vertical reference line.

Tighten the screws on the scope rings gradually and evenly to prevent any minute rotation of the scope.

After the screws on the scope rings have been fully tightened make a final check of your work:

1. The vertical reticle instrument has four points of contact.
2. The bubble is centered exactly between the calibration marks.
3. The vertical crosshair is exactly parallel to the vertical reference line.

The procedure is now complete and you have successfully aligned the vertical crosshair of your scope accurately with the center of your bore.

Diagnostics and Troubleshooting using the Vertical Reticle instrument



The Vertical Reticle instrument will perform an accurate reticle-bore alignment regardless of any misalignment of the scope body itself with the centerline of the barrel. When a significant misalignment does exist between the scope and firearm, the Vertical Reticle instrument can expose this problem, therefore enabling you to take corrective measures.

If after the completion of the third part of STEP 3 of the reticle alignment procedure it is noticed that the firearm itself appears or tests out to be leaning slightly to the left or right,see illustration #4) when the other conditions are met, this is an indication that: l ) Either the scope body itself is not mounted at top-dead-center above the action and/or 2) The alignment of the scope body is skewed with the axis of the barrel.

The second condition is easy to remedy if the scope mounting system includes windage adjustments. Otherwise both conditions can be difficult to correct and may not be worth the trouble. A "cosmetic" and serviceable reticle alignment can be performed by placing the Vertical Reticle instrument on the end of the stock as shown in illustration #4 and performing the tasks of STEP 3 again.