Sighting in any optic without using any ammo

[MountainBear]

Your friend doesn't need $200 for a laser boresight device, but could pick up a used collimitor at a gunshow for $10 and probably be just fine.
I get your point, but at some point is what you are doing worth the time it takes? For me, having been a gunsmith for ten years and already having access to very high quality measuring tools, it's still not worth it. Too much time, even for a personal gun. A bore collimitor was one of the first tools I bought.

But you are right, like I said, in theory, removing a bunch of possible variables, your method would work.

 

[jbett98]

You can center a scopes cross hairs by placing it tight against a bathroom mirror with the light on above it.
When you look into the eyepiece you will readily notice two sets of cross hairs, especially if it's been used on another rifle.
All you have to do is adjust the elevation/windage knobs to line up both sets till they're one.
Some scopes don't take well to winding all the way over to one side and then the other.

 

[Member 34319]

Your friend doesn't need $200 for a laser boresight device, but could pick up a used collimitor at a gunshow for $10 and probably be just fine.
I get your point, but at some point is what you are doing worth the time it takes? For me, having been a gunsmith for ten years and already having access to very high quality measuring tools, it's still not worth it. Too much time, even for a personal gun. A bore collimitor was one of the first tools I bought.

But you are right, like I said, in theory, removing a bunch of possible variables, your method would work.

Does it help you if I stated I'm a bit of a math dork?

But, I'll respectfully disagree that this is theory, there literally is a mathematic equation for just about anything firearm ballistics.

I took a few long range shooting classes and they really opened my eyes to the simplistic nature of ballistics and firearms. That is of coarse if your like me and geek out on mathematics.

 

[MountainBear]

It's all theory to me until I pick up micrometer, caliper, angle gauges, etc. and put measure to metal for myself. I don't doubt the math, but my experience makes me doubt the variables and the stacking of tolerances.

If it helps your geek out, power to you. I have my quirks as well (I talk to my guns, no big deal).

 

[Member 34319]

It's all theory to me until I pick up micrometer, caliper, angle gauges, etc. and put measure to metal for myself. I don't doubt the math, but my experience makes me doubt the variables and the stacking of tolerances.

If it helps your geek out, power to you. I have my quirks as well (I talk to my guns, no big deal).

You did make me go dig out my dads old collimiter out of where it was hiding.

 

[MountainBear]

I bought a used Tasco collimitor at a gunshow in Denver when I was still in gunsmithing school. Think I paid $10 or something. Used it hundreds of times, usually get compliments from customers as to how close it gets them. Takes less that two minutes.

 

[Member 34319]

I made one mistake in my first post.

I always forget up is down and down is up when it comes to scopes.

IE when you adjust up, your angling down. The line of sight is lowered when you adjust up. When you aim again after adjusting you'll point your scope straight and the barrel is now angled upward.

So in my original post where I said you would adjust down 2 minutes of angle I was wrong, you would be adjusting up 2 minutes of angle. Which would lower the angle of your scope 0.0334 degrees or roughly 2" at 100 yards. When you proceed to aim again your optics line of sight is straight, and you'll then be angling your barrel up at the newly created angle.

Same goes for my post about optics off center to the left.

Even I still get confused sometimes.

 

[ron]

Or semi-auto's like an AR.

Too many variables. Tolerances add? Boresighting an AR is easy. On paper with first
shot @ 100 yards. From the bench at 100 yards pull out the bolt carrier sight down
the barrel and set it on the target. Adjust the optic in the opposite direction.

 

[IronMonster]

I clicked looking for something "easy" and you go all math and stuff.

I'll just shoot 5 times and adjust. I like to shoot.... I don't like to math.

 

[11Charlie]

I picked up a $10 laser sight and it gets me on paper every time!

I have to agree with everyone that Math just sucks!

 

[v0lcom13sn0w]

thats awesome. i use about $5.00 in reloaded ammunition to zero my rifles, i dont have to think, all i have to do is shoot and adjust.

 

[P7M13]

Long reply - no math, common sense and some tools needed.
When I help people sight in, they always ask about the dial arrows and directions. I tell them, the arrow and word (i.e. UP ->) moves the bullet up if you turn the dial in that direction. If you're going from where you aimed to where the hole is, you turn in the opposite direction, meaning, if your bullet hole is above where you aimed, you turn opposite to the UP arrow direction.

I'd like to add a few suggestions, sans math:

1. ABSOLUTE: Your rings must be aligned as accurately as possible. If you're mounting them on the tapped receiver holes, strongly recommend using the alignment dowels. If you're not aligned properly, the rings impart a minor bend in the tube. Then, if you need to adjust your dials, the error between the dial and the accuracy increases with the flex of the tube over distance, being worst opposite of the tube bend angle. As a user, you'll just think it's wonky. If you're doing a scope tracking test, it will be wrong. On a Picatinny scope mount, mount the rings loosely to the rail, mount the scope loosely, and then, like bolting a head back onto an engine, move through the bolts applying successively increasing amounts of torque.
   
2. If you're going to shoot long distance, leveling your reticle is also a must. I have a jig with a Picatinny rail, adjust everything level, mount the scope and then align the vertical cross hairs with a fluorescent plumb line, hanging approximately 25 yards away. To level my jig, I use both a bullseye level and a Wixey absolute angle gauge (gets you within 0.1°)
3. If you ever want to level your barrel (bolt action), on every rifle I have ever worked on, the bolt ways (remove the bolt, those two flat surfaces on either side of the receiver where the bolt glides), will always be aligned with the receiver holes. I use a Starrett angle measurement tool, clamped down to the ways, where I can use the extended surface to mount my level. The Starrett is ground and stiff enough so the level doesn't cause it to flex.

Mounting the Scope

1. Go to Gundata.Org ballistics calculator, select the cartridge you will be using or closest to your reloads. For the example here, I selected a 308 Win Rifle, using Hornady Amax Match 168gr bullets, and a 100 yard zero. A 40mm objective with standard rings will usually be 1.5" height over bore (centerline of scope optical axis to centerline of rifle bore).
   If you think of your scope optical axis as a laser, the barrel, relative to the scope, points up at a very slight angle. The bullet necessarily arcs in it's flight path, crossing zero twice - once part of the way to the target, and theoretically at the target.
   Using the 308 example above, this is what the ballistics calculator gives me for the flight path:
   
   Note that the bullet crosses zero at approximately 58 yards. Since most people don't have that distance to stretch, I will set up a plumb bob line and measuring target at 21 yards (this example).
2. Mount your rifle in a vise (or some other way to hold it firmly in position).
3. This step is not critical, but helps for accuracy: Completely level the scope for horizontal.
4. Remove the bolt on a bolt action rifle, remove the lower and bolt on an AR.
5. Back before I bought a bore laser from Sportsman's Warehouse for $20, I would sight down the bore at a bead on the string. Parallax is important here -- the bead needs to be completely concentric in the bore window.
   If you look at the example photograph I stole off the web, the barrel / bore / target circles are not concentric. perhaps this is the photograph, but you need to have these dead on. Now I'm lazy and use the laser bore sighter.
   
   
6. If you are using a laser bore sighter, once you have it mounted, rotate it in the barrel and verify that the laser spot does not move as you rotate.
7. In the example above, at 21 yards, you will need another bead at 0.75" below the bore sighting bead.
8. The vertical crosshair should line up exactly with the string (overlap), the horizontal should line up exactly with the center of the lower bead.
9. Put your caps back on and take a test shot.
10. To finalize, with your rifle in a vise, put the crosshairs exactly where you were aiming, then move the crosshairs to where the bullet hole is.
    Some guides will tell you to do this step using three shots, then move your crosshairs to the geometric center of the three shots.

Recently I changed scopes on my 7mmLRM and followed the above procedure. I set the ladder/string at 30 yards and aligned the laser mark and crosshairs. My first shot was 1/2 to the right and 4" high at 100 yards (only able to test at night). Since the ballistics of the bullet are for 3" high at 100, I adjusted my dials. To check, I then did a tracking test, moving the turrets 3" down, and my next shot was dead-center bull.

It's all theory to me until I pick up micrometer, caliper, angle gauges, etc. and put measure to metal for myself. I don't doubt the math, but my experience makes me doubt the variables and the stacking of tolerances.
If it helps your geek out, power to you. I have my quirks as well (I talk to my guns, no big deal).

Stacking tolerances - excellent point.

 

[Caveman Jim]

Math is hard.

Yup, real harrd ifin yer dumm....

 

[American123]

Does it help you if I stated I'm a bit of a math dork?

But, I'll respectfully disagree that this is theory, there literally is a mathematic equation for just about anything firearm ballistics.

I took a few long range shooting classes and they really opened my eyes to the simplistic nature of ballistics and firearms. That is of coarse if your like me and geek out on mathematics.

This is correct. There is a mathematical equation for everything related to ballistics and trajectories (except the magic of barrel harmonics)

As long as your input data is correct your result will be correct too. You just have to make sure your input data is actually correct. That's exactly how they come up with trajectory tables, they have an equation and you fill in the inputs like BC, velocity, weight, temperature, altitude, etc. speaking of which, I need to get that project done which was to create a trajectory chart for each of my rifles.

I would never pay $200 for a laser sight system, but I did pay $70 for one that works with the "Itarget system" and in addition to he GF practicing dry fire with that. I can also use it to sight in rifles.

 

[CarlMc]

I worked with a precision lab firearm for a project at work and got to play with a variety of them at about 20 feet. Any laser sighting tool sucks, and the most expensive ones only suck slightly less. They get you onto paper. No more. The rest is a waste of money.

I wound up mounting a pistol laser on a bracket on top of the gun, aiming the laser at the center of the point of impact, and providing we didn't move the target, that was the best we could do.

 

[best defense]

That is all good, and it is certainly what should get you on paper.
Now one little trick that will work from there on,
When you have sighted and shot at the center of the target, but the bullet didn't hit the center of the target, scoped rifles have one small advantage. Set the rifle up on sand bags and aim at the center of the target. Then without moving the rifle, dial the cross hairs so they are aligned with the bullet hole you just made with the first shot. That works well for most people, and it eliminates guess work about how many minutes you should dial to get the job done.

 

[Idaho44]

Inexpensive Tasco collimitor plus this:

Group of three does the trick and you only need about a 25 yard aiming point!

 

[Defense Minister]

If I can see down the bore with the bolt or action removed I set the rifle on a solid rest, pick an object at 50 yards, move the rifle/rest so that the object is centered while looking down the bore (pay attention to minimize parallax), and adjust the scope to match. This won't produce a precision sight-in, but neither will other methods that don't involve actual shooting. You can play college math professor if you want, but this method is easier...

 

[titsonritz]

Screw that, I want to shoot it.

 

[dangerranger60]

If I can see down the bore with the bolt or action removed I set the rifle on a solid rest, pick an object at my sight-in distance, move the rifle/rest so that the object is centered while looking down the bore (pay attention to minimize parallax), and adjust the scope to match. This won't produce a precision sight-in, but neither will other methods that don't involve actual shooting. You can play college math professor if you want, but my method is easier...

You method will work because it takes the ammo into the process. just by swapping bullets [ keeping the same velocity] I can change the point of impact. Sometimes by a lot!

I have used a dental mirror to bore sight semi auto rifles before. But it only gets you close. The ammo is the other part that has to be shot to be sure.

We have a LGS that "Lazer " sights rifles , and hands them back claiming that they are right on at 100 yards. When I ask about it they said "It's closer than most of these guys can shoot"! DR