New York Firearms Forum banner
1 - 11 of 11 Posts
G

·
Discussion Starter · #1 ·
The purpose of "leveling a scope" is to ensure that the line of sight is directly above the axis of the bore.

What is meant by "leveling a scope" is broadly misunderstood. The outside of the scope is irrelevant to this process. The reticle and elevation adjustment mechanism are the critical elements in this process and they may not be aligned with the outside of the scope.

The first step in this process is leveling the rifle. This is best accomplished using a spirit level that attaches to the scope base. These types of spirit levels can be referenced while setting up your firing position later on so as to ensure there is no "roll" cant in the rifle.


With the rifle level and the scope mounted in the rings and the rings attached to the scope base view a plumb line some distance away (80 to 100-yards). Roll the scope in the loosened rings to align the vertical component of the cross hair with the plumb line. Once this alignment is achieved carefully tighten the scope rings to the scope.


Now, with the rifle perfectly level the vertical component of the cross hair will be straight up and down. Assuming that the horizontal component of the cross hair is normal to the vertical component the horizontal hair will be level. And the intersection of the crosshairs (line of sight) will be directly above the line of the bore.

If you plan to use the elevation dial on the scope to adjust for range it's important to determine that the hair crossing (aiming point) will track straight up. This can be done using live fire or using a laser bore sighter.


With the weapon system zeroed at 100-yards place a tall cardboard backer at 100-yards. Using an aiming point near the bottom of the backer mark the spot where the laser dot lands then dial into your elevation adjustment a substantial amount of elevation, say 40-minutes of angle (moa). This should subtend a distance at 100-yards of 41-7/8 inches. With your cross hairs held on the aiming point mark the point that the laser hits. Use a hand-held plumb line to determine that the laser dot is exactly above the previous laser dot location. If that laser dot isn't directly above the previous point it means that your elevation adjustment mechanism inside your scope it out of plumb and you'll have to make your corrections with this in mind.

Example:
The distance tracked is actually 38-1/2 inches then you know that your elevation dial is only giving you 92% of the true adjustment. (No scope is perfect so don't sweat it.) This means that if you want 40-minutes of angle adjustment you'll have to dial in 43.2-moa on your scope. Just multiply what you want by 1.08 to compensate.

If the second laser point is 2-inches left of plumb after dialing in 40-moa you know that for every moa you dial; the crosshairs move 0.05 moa left. So if you want to correct for this simply add 0.05 moa of right windage for every moa you dial up.

Example: 10-moa up, add 0.5 moa right.

Just keep in mind that the outside of the scope doesn't necessarily reflect what's inside.
Keep a spirit level on your rifle to avoid roll cant.
Properly level and check your scopes reticle.
With these things done properly you'll convert many unexplainable misses into hits.
 
G

·
Discussion Starter · #5 ·
Friday Off: Check
Good Weather: Check
Chores Done: Check

So I took my M700 .223 to the range to practice and to fire-form some more brass.


I figured that while I was at it I'd calibrate my scope using the live fire method. So, after confirming my 100-yard zero on the bottom orange aiming point I dialed in 32-minutes of angle on my elevation turret. This was four full turns of 8-moa each. The click increments on this Leupold 35X target scope are 1/8-moa.

I then shot a five round group while holding on the original aiming point. My group piled up 33.125-inches above my aiming point. This is a shift of 31.64-moa.


31.64-moa/32.00-moa = 0.98875 or 99.9%

I'll take it.
 

·
Registered
Joined
·
218 Posts
kevin, a buddy of mine has a leupold VX-3 8.5-25x on his mcmillan 50. I do like how it feels while shooting. it has great eye relief. Any experience with one? I have a 10x on another rifle of mine and dont mind a straight power but thought the 8.5-25x a nice addition. I want to put it on a 308 build that i am talking with Dan about.
 
G

·
Discussion Starter · #7 ·
I had a Leupold VXIII target scope on my 6.5-.284 a few years back, I liked it.

Regretably I sold it..


10X is fine for shooting steel and meat......not so great for these paper matches with teeny-weeny X-rings.
 

·
Registered
Joined
·
218 Posts
i have looked at exactly that scope as well. after shooting on my own in my back yard i have thought about getting started in the F-class shooting. would that or the 8.5-25X work for that? keeping in mind that i will be also using it at home at varying ranges. I agree that the 10X is best suited for steal and meat. I have it on an AR so that works well.
 

·
Registered
Joined
·
74 Posts
Thanks for the great info on leveling and calibrating a scope Kevin, I always just eyeballed mine so it looked like the vertical cross hair was pointing to the center of the bolt but I'm all for precision and I will give this a try.

Dan
 
1 - 11 of 11 Posts
Top