Aligning scope to bore parallel?????

RoyB

Member
Aligning scope to bore parallel?????

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?
 
Scope parallelism

Pick the distance at which you would like to shoot.

Then I'm thinking use two lasers to line it up.
I have never tried this but it would line you up with your target pretty good.

Just a thought.

John
:D:D:D
 
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 Reticle™ 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.
 
Aligning scope to bore parallel?????


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?
If you are using Leupold or Millet type rings, the adjustable kind, center the windage adjustment on your scope. Then, at the range, using a stable bag setup, boresight on something a good distance away, at least 100 yards.

Then adjust the rings so the cross hair is as close as you can get it. That should be close enough for hand grenades and horse shoes, and scopes.
 
I don't care for windage bases and don't use them, but if I wanted to make sure the tube was true to the bore I would center the erector assembly in the scope tube, then use the windage mount screws to set my initial zero/bore sight:

http://www.usoptics.com/index.php?page=instructions

Cheers,

Bill

Edited to add: What Jerry said - he beat me....
 
Last edited by a moderator:
But all of the above methods only assure the scope is aligned at one particular spot in space. If you did the above at 100 yds, that is the only spot in the universe that you can be sure the reticle is aligned with the bore. If you now sight in on something 500 yds away, unless the scope is perfectly parallel with the bore of the barrel, your shot will go either right or left. And this is compounded even more if you "click" up and down at different ranges, because now a very slight cant of the verticle crosshair is greatly magnified as you move the crosshairs up and down.

The method of hanging a weighted string some distance down range, and then bore sighting onto that string (or using a bore sighted laser) and then lining up the crosshairs on the string still only accomplishes a "one point in space" accuracy.

Someone must have thought of a better way to accomplish this task.......You would think the 1000 yd boys would have this figured out......
 
If you're using the Burris Signature rings just put a little degree of offset in the inserts after centering the adjustments on the scope. I wound up with a 20 moa insert in my rear ring and a 5 moa insert in my front ring. I wound up with about a 30 degree rotation on the 5 moa insert to get my scope aligned. Do this while using a bore scope. Several trial tightenings of the rings may be necessary to get to the right point.
 
You repeated the question at another site, I'll repeat my answer here. :D

Which do you want? You are describing two separate things. related yes, but separate.

If you set your scope up and get the crosshairs optically centered, and use the scope mount windage adjustments to get dead center left/right at 2 extended ranges, then you then know that the scope tube is parallel to the bore. If it is centered at one range and off at the other then you know that the scope is not mounted directly above the bore. You can correct some of this through trial and error by repeated shooting at both ranges and alternating the adjustments between the front and rear mount adjustments. If you are dead on at 100 (and got there by adjusting the front mount), but are hitting to the right at 150 or 200 (and wind and rifle cant is not the issue). Adjust the rear mount to get to L/R zero @200. This will put you off at 100 again, but by an ever decreasing amount.

At no time during this exercise should you even think about touching the scope windage/elevation knobs.
The scope should remain optically centered in it's tube during the whole exercise.

Only then can you start to worry about whether or not your reticles are square with the world.
 
Last edited by a moderator:
TAke a peice of 1" stock & machine a hole into the exaxt center of it that will allow a small lazer to fit in it snug,This goes into the Rings & is put on target at say 50 yds or whatever.You know that the lazer is in the center.Now you need one of the lazers that fits into the bore of the rifle.You can now adjust what ever to align the 2 dots,you can not reley on a scope to be centered perfect,If you need one for 30mm,Make a second one to fit the 30mm rings. BILL
 
Bill,

Your "laser" device will still only give me "one point in space".......no different than simply bore sighting and then aligning scope to hit where the bore is pointing. But again, only at that specific range..........

Nope...There has got to be a better method..........
 
Using two targets at two different ranges,(50 and 200 might work best) is the best idea. But then you have atmospheric conditions to deal with (wind).....

There has to be a way to use an indicator rod down the bore and a 1" piece of drill rod in the scope rings and some way to align between them.........
 
I don't understand....

how could using drill rod in the gun and rings get you any different result than the method proposed by a few guys with the lasers????

My second question would be....why so hung up on parallel, almost all the guys use one or more of the methods described in these replies to bore sight and align their scopes.

Just curious.
Linc
 
Scpoe alignment

One thing you might consider, unless the bore is exactly in line with the receiver point of impact wil change as distance changes as there will be an angle between the barrel and receiver where the scope is mounted, the gun will always be shooting sidways and all you can do is adjust point of impact as the range changes.

Dennis
 
The laser would work if you did the alignment in a smoke filled room, where you could see the laser beam as a "line of light" rather than a dot in a predetermined target distance. But you would still need some method of correlating the beam of light to the bar resting in the scope rings..........

The bore and the center line of the scope needs to be perfectly aligned otherwise as the distance changes, the convergence of the bore and the center of the scope will change left or right...........

All of the methods listed thus far do not take into account this issue......
 
Roy,I think that now understand what you are after,What you need to do ,is use 4 lazers,One in each end of the 1" bar & one in each end of the barrel,You will have a set of lazer dots in each direction & thus ,you can see how much misalignment you have between the barrel & the action mounted rings.The Barrel will need to be straight or the lazers will not show a truebore line.You could set it up in a room & use the wall in opposite directions for the course alignment & set them farter apart for a fine tune.I do not know where you can get the lazer for the chamber end,you might end making a adapter yourself. BILL
 
I realize I am not a benchrest guru, but as long as the crosshair is centered what difference will it make if the scope is not one hundred percent inlined. Perhaps I am missing something, but I don't see how a slight misalignment can change point of impact (left to right) as long as the cross hair is zeroed?
 
Bill,

Excellent idea, and that would work! Both "sets" of lasers would need to hit two vertical lines in front and rear of the rifle, drawn on opposing walls............Perfect!

Thanks
 
Jackson...............I hope this "CAD" (Crayon Aided Drawing) helps explain what I'm talking about.

I understand that the misalignment will be very little, but it would be nice if when you click "up", the bullet simply went up and not left to right some amount......

misalignment2-vi.jpg
 
Back
Top