Plumb Bob for Aligning Scope

[DBlue]

I got tired of fooling around with small plumb bob's always moving with the slightest breeze while trying to align my scopes. I machined a large plumb bob out of 2" diameter solid aluminum round bar and that took care of the problem....got all my scopes aligned today and it does make a difference, especially when going from 50 yards to 100 yards and further...

 

[Bill_D]

I always used a 24" square mounted on a post - Level it up with a pump bob - for me it seems to be a lot easier process when you have a vertical and horizontal reference to line up on.

 

[Struckat]

No matter the method, or combo of methods, I find it only gets it close.
You still need to shoot and click up and down to see if it tracks.

 

[starlingassn]

plumb bob is just used to set your scope level to read level,

now use the mirror method to align the crosshairs to the bore,
and youll wonder why you ever did it any other way

 

[starlingassn]

get a mirror,


set it up at say 5yds,
set your scope to 10 yds (or when its focused in the mirror)


look through the scope at your reflection in the mirror (a steady gun rest helps)

loosen the scope ring screws and rotate the scope till the vertical crosshair intersects the center of the bore when the crosshairs are centered on the scope objective.

"bam" your crosshairs are now aligned with the bore

snug your ring screws and recheck,
repeat till perfect


then use the plumb line to get your vertical line,
adjust and lock down your scope level,

now everything is lined up and if you miss its your own fault LOL

 

[bigHUN]

a diy levelling tool and a flashlight to project the reticle back to the plumb bob

 

[starlingassn]

as an example,
this is what you are hoping to see through the mirror,well,minus the ugly fat guy lol

crosshair centered on the scope objective,
and vertical crosshair splitting the bore.

 

[Star7]

Absolutely the finest plumb Bob I have ever seen!

 

[EncoreUneFois]

Plumbob SquarePants! Top job.

Mirror thing though makes me think it is the way to go.

If you set your scope to a plumb then you need to ensure your rifle is also dead level. That gives you two variables to maintain. The mirror thing takes one out so will inherently make things more likely to be accurate.

To be fair, you are reading the words of a man who has hitherto relied on the spirit levels built into Tier1 mounts and Mk1 eyeball regarding the scope being level with the chassis.

I will try the mirror and see how far off I am.

Lovely bit of work though!

 

[DBlue]

Plumbob SquarePants! Top job.

Mirror thing though makes me think it is the way to go.

If you set your scope to a plumb then you need to ensure your rifle is also dead level. That gives you two variables to maintain. The mirror thing takes one out so will inherently make things more likely to be accurate.

To be fair, you are reading the words of a man who has hitherto relied on the spirit levels built into Tier1 mounts and Mk1 eyeball regarding the scope being level with the chassis.

I will try the mirror and see how far off I am.

Lovely bit of work though!

Plumb bob Square Pants….lol

Yes, you have to make sure the rifle is perfectly level before aligning with the plumb bob. I’ve got several different levels to get the gun perfect level before aligning with it. Just for the hell of it, I did check it with the mirror and flashlight method and it was dead on but most people probably would not spend the time that I did getting it right as I’ve got OCD when it comes to this kinda stuff….

 

[Martin3528]

That is a cool plumb Bob, but unless you are trying to plumb it over a specific point, all you need is a weight on a string. You can make a vertical with a brick on a string.

 

[starlingassn]

That is a cool plumb Bob, but unless you are trying to plumb it over a specific point, all you need is a weight on a string. You can make a vertical with a brick on a string.

exactly


i use a big round magnet with a hole in the middle,
when im done adjusting my scope level,
i stick the magnet to the arm i have the string mounted to and it keeps it out of the way.

creativity is magical lol

 

[DBlue]

There are a multitude of different things that could be tied on the end of a string to make a vertical line….I have a small machine shop here at my home with two metal lathes, two milling machines etc., etc….I chose to machine a large plumb bob because I could….that’s the way I roll…

 

[Martin3528]

There are a multitude of different things that could be tied on the end of a string to make a vertical line….I have a small machine shop here at my home with two metal lathes, two milling machines etc., etc….I chose to machine a large plumb bob because I could….that’s the way I roll…

No disrespect intended. I am land surveyor and until recently a plumb bob was on my hip at all times. I would not want to carry that one around!

 

[Southerngunner]

I use a blank piece of cardboard on my target stand with a sharpie, a 24" level with a line vertical and horizontal works for me at 25 yards.

 

[bustachip]

I use a blank piece of cardboard on my target stand with a sharpie, a 24" level with a line vertical and horizontal works for me at 25 yards.

I do the same and the wind doesn’t affect it, it’s just as good as a plumb line.

 

[Sawney Bean]

I have entire range set up of hanging targets. These days I'm mostly using padlocks, but I've used galvanized pipe fittings, miscellaneous hardware, basically anything metal that's the right size I'll just hang on a string so I've got a dozen or so improvised plumb bobs to align my scope on at any given time.

 

[Frank in Fairfield]

A 3 pound hunk of lead tied to a string.

 

[theLBC]

lol, love it. if you happen to have power or telephone poles, those are generally pretty decent outside of hurricane areas.

 

[Healthservices]

I see a lot of faults with many of the methods described on the forums.

Let's see of I can stir the pot more without hurting anybody...

And the below is extreme visualization so it can be understood and seen.


We put a level on a the picatinny rail and level it, so it is assumed that the barrel centerline is perpendicular to the pic rail.

With this leveled you look thru your scope and see the plumb Bob line.

You rotate the scope in the rings until the retical's center vertical lines exactly to the plumb Bob line.

So the scopes retical is perpendicular and square to the level on the pic rail right?

So this must mean if you draw a straight line from the scope center to the barrel center the retical, and its center vertical line is perfectly lined up with this centerline right?

Nope, not necessarily.

So the below picture is the best without photoshop but hopefully with this visual you can see that drawing a line between scope center and the barrel center, it does not match up with the scope's retical. Thus the scope/barrel centerline can be canted from using a plumb bob.

So even though the pic rail was leveled, and the scopes retical was lined up to the plumb Bob line.

This basically means it is not the same or a good as using the mirror method like in this picture below.

I hope that worked the way i try to convey it and you can see what I mean. The plumb Bob method assumes the scope's vertical centerline is already in line with the barrel's center and because of that it can easily be wrong. I'm not saying the plumb Bob line is not perfectly vertical.

I hope I'm not wrong in how i understand the different methods and how they are better than the mirror method. If I am wrong hopefully you can explain it in a way I and others can understand.

Thanks


Allen