Ideally, when you want to change out the scope on your rifle, you use a leveling rifle vise or let a gunsmith to do the job. However, not everyone wants to or can spend money on that kind of thing. Plus, you might find yourself in circumstances where neither is an option.
Take heart! I’m going to show you a fantastic hack, which lets you switch out a rifle scope or shotgun scope at home for basically nothing. All that’s required is some patience, a bit of fiddling with the procedure and a few common hand tools.
Bear in mind, I’m not saying that you shouldn’t use a rifle rest. I’m not saying you shouldn’t follow manufacturer recommendations. And I am definitely not saying that you should do this if you don’t feel comfortable.
This is a low-tech, DIY method for mounting a scope if you don’t have the specialized tools for the job.
Some folks might point out that what I’m about to describe isn’t a new idea. And they’re right. People have been doing it this way for years. Phil Bourjaily mentioned basically this same idea in Field & Stream a long time ago, so it’s not like I’m revealing any government secrets here.
Also, this presumes you’ll be using the same rings and/or base to mount your new scope. We may revisit the topic at a later date, but for now let us focus on changing out only the scope. In many cases, that’s actually all you need do; since most riflescopes on the market use the same diameter tube (1 inch, though some are 30mm) it’s not always strictly necessary.
I must also apologize, in advance, for the crappy quality of the photos you’ll see momentarily. I left my camera at the office and had to rely on my phone.
With that said, let’s get to work.
Tools You’ll Need To Change Your Rifle Scope
You will need:
A good, stiff cardboard box. Try to choose one with tall sides; 8 to 10 inches works pretty well, with at least that in length. You don’t need a picture of that, do you?
Material for shims. I recommend scrap cardboard, but use whatever.
How It’s Done
First, take your old scope off of the rifle by loosening the Torx screws holding it. Set the top rings and Torx screws aside.
Take your new scope and lay it in the rings and figure out where it needs to be mounted — front to rear — for proper eye relief. The more the better; there should be at least three to four inches between your eye and the lens. Note where you’ll need to set the scope.
Set the cardboard box on a level-ish surface. You can use the floor if need be. I used a stool.
Cut one flap off the box. This is where you’ll rest the butt. Top tip: cut three of the flaps off, and cut your shims from them. Make a cut straight down in about the middle of the box in the section where you’ve cut off the flap, maybe an inch in length.
This cut is the spot you’ll rest the butt on. If you’re performing this operation on a bolt-action rifle, you’ll want to cradle it just behind the pistol grip of the butt to keep it steady.
Place the rifle in this improvised cradle, laying it back-to-front by placing the butt in the cradle first.
Make sure the rifle is stable in the cradle. Using the spirit level, check that the gun is level from front to back and side to side. I found the best way to check front-to-back level is to rest the level in the scope ring bottoms and on the mount between them (which, on mine, is flat; I have a Leupold base and rings) for side-to-side.
To get level from front to back, you simply shim the front of rifle up to plumb.
For side level, you’ll want to gingerly move the rifle to one side or the other until you get inside the lines. Then, gently press straight down on the butt, pushing the stock into the notch you cut in the rear. You’ll notice in one of the above pictures that it ends up making a “V” in the the box. It won’t seat all the way, it will just set itself securely.
Once the bubbles are in the lines side-to-side and front-to-back, place your scope in the rings, taking care to gently seat it where you need it to be for proper eye relief.
Then rest the level on the top turret, re-checking level front-to-back and side-to-side. Gently place the ring tops back on top, and start screwing the Torx screws in. Best practice is to put a bit of blue Loctite on the threads before you seat the screws (if you have some available). Don’t fully tighten the screws. Re-check for level.
It helps if your spirit level has a notch on one side; it’ll fit perfectly on the scope turret.
Now, you need to confirm you have level crosshairs. Some people do this with a plumb line or by pointing the rifle at window trim. I used a different method.
Look through the scope; you should see the wall or a door across the room. Note the location on the wall or door that you see in the scope.
Take some scrap cardboard you cut from the box. Go to the wall, door or what-have-you that the scope picture is of. Tape up the piece of cardboard top and bottom, securing it to the surface.
Using your spirit level and Sharpie, draw a crosshair, with a plumb line from top-to-bottom line and a level side-to-side line. Go back to the rifle, and look at the piece of cardboard. If you have to, move the cardboard piece until the crosshairs of the scope are aligned with that on the cardboard. Don’t move the rifle!
If they line up, you’re done! Tighten the Torx screws in the rings the rest of the way in a criss-cross pattern for even tightening. Don’t over-tighten them, but make sure they are securely seated. If you have a torque wrench, the typical factory setting is 18 ft-lbs.
After that…it’s time to take your rifle to the range and get it zeroed.
And there you have it. I didn’t have to spend a dime on tools or supplies, and I got a better optic on my rifle — a Vortex Diamondback Tactical 4-12X scope — on my Model 70. Deer season is about six weeks away, so I have plenty of time to get it zeroed.
Bambi delenda est!
Is it as good a method as buying a leveling rest with vise mounts? No, it’s not. But it’ll do.
Anyhow, sound off in the comments if you’ve ever used a method like this to install a rifle scope or shotgun scope. Again, this isn’t a new method; people have been performing this operation for decades. However, this will hopefully give the newbie an idea of how they can change a scope on their own without needing as many gadgets as some people say.
Or just clamp an old magazine in your garage vice and level, done.
I just use the level on my phone. Zero the level on the top of the receiver. Soft mount the scope, tweak it until it levels at 0 relative to the receiver. Tighten, check the level. Done.
Provided your rifle has a good bipod, this is a five minute evolution.
thanks for such s useful post <3
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I don’t see the point of leveling your rifle’s bore axis (from muzzle to buttstock) before mounting your scope unless it is to establish a fairly level surface on your scope’s elevation knob.
And I do not see how you can possibly determine level (left-to-right) on a rifle, unless you could insert a rod into your muzzle, which holds the weight of your rifle, and then align the middle (left-to-right) of the butt-end of your buttstock with a plumb line on the center of that rod in the bore axis. In case it is not obvious, such a contraption sounds impractical.
Just saw this…..
https://www.foxnews.com/us/colt-suspending-production-of-ar-15-for-civilians
Virtue signaling since they are overpriced in the market?
I saw that also,
I think they said they were going to focus on military and LEO contracts?
Honestly I think their rifle sales on the civilian market are tanking because they are over priced compared to the competition which is every bit as good for usually almost half the price.
I have read that they have contracts to fill and that’s why they are doing this.
I’ll try and find a link.
I understand that Colt lost the U.S. military contracts in 2013 to FN, which is producing a superior product.
I wonder whose militaries Colt is building their rifles?
The Army was getting/had both Colt and FN rifles before I got out in 2009. The last issue rifle I had was a brand new FN.
Was written about on this site a week ago: https://www.thetruthaboutguns.com/colt-halts-sales-of-long-guns-to-the-retail-market/
Most of the stories out there are all saying the same thing, the production halt is temporary. Many estimate it at 60 days. They feel there is enough supply in their inventory and want to focus on getting government contracts out the door.
Thanks for the link,
I hadn’t read the follow up on the story.
Colt’s press release makes it sound a lot more like it is indefinite.
It’s indefinite. Colt benefited from lack of knowledge for years in which new buyers asked “which AR 15 is the beSt”. Now the secret is out, Your poverty pony or PSA rifle is as good as any
18 ft/lbs or 18 in/lbs?
Inch pounds!
Some folks have ruined a perfectly decent scope by using foot pounds.
I haven’t seen a scope with a one inch tube in ages, but perhaps that’s because of my application?
Millennials! (Just a guess).
When I mount a new rifle scope, the very first thing I do is determine proper location for eye placement (e.g. eye-relief, how far the scope rests toward the butt stock).
Next, I attach the top of the scope rings, just loose enough that I can twist the scope in the rings to make the cross-hairs level/plumb, and not so loose that the scope can easily slide forward or backward.
Finally, I stand up and hold the rifle as I would hold it if I were shooting off-hand, making sure it seems to be plumb in MY grip. Once I am convinced that I am holding my rifle plumb, I look through the scope at the edge of someone’s home or window (which should be plumb). If my cross hairs do not line up with the neighbor’s window, I use my trigger hand to twist the scope until they do, rechecking that I am still holding the rifle plumb after bringing my trigger hand back to the stock.
Once I think my scope’s cross-hairs are level/plumb, I tighten down the rings.
This method is exceedingly easy and fast, only requires one tool (to tighten the screws in the scope rings), and it works! Perhaps a hidden benefit to this method: it aligns your scope’s reticle with the way that YOU naturally hold your rifle and shoot.
Proper eye relief and having the cross hairs plumb/level when you’re aiming the rifle are all that matters. Yes, if the cross hairs don’t align with the rifle bore it will throw your point of impact off by 1/16th or maybe 1/8th inch, but if your vertical cross hair isn’t plumb when you fire it could throw you off by several inches of even feet on longer shots.
I always did it this way and then I was “informed” I was doing it wrong. Unless shooting in a vice with levels in the field, this method is more than good enough. It is tuned to all my imperfections.
Geez all that? I’m a 65 year old novice and I figured out all that mounting a scope stuff on the myriad #’s of YouTube videos. And shooting,sighting in,changing a forend,attaching a light and a red dot sight…if I never hire “help” I’ll be a happy old fart😏
When I saw the title of this post, I thought the article would tell us to:
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(1) Rigidly clamp your rifle in a vice, noting exactly where the cross-hairs point and how the reticle is aligned (in terms of level/plumb).
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and then
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(2) Put the new scope on the rifle (without moving the rifle) and adjust the reticle until it matches the previous alignment and point-of-aim.
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And then, voila, your new scope is mounted and already aligned and on-target (assuming that your previous scope was properly aligned and on-target).
I have a simple device that works with a laser on one end and a small arbor on the other. The arbor fits into the muzzle of the rifle which is about .30 caliber. All you need to do is point it at a white object near dusk at approximately 25 yards and it will show you within a inch of where the bullet is going to strike. Remove the arbor and take it to the range. Scope will hit with an inch at 100 years. I think it cost me about 20 bucks but that was over 30 years ago.
Sorry. Not years obviously, but yards.
That’ll work fine at 100 yards. As you reach out farther and farther, not having the scope square with the receiver will start to bite you in the butt.
Raz-O,
In case you intended to respond to my comment that I “square” my scope according to how I hold my rifle plumb (rather than using fancy contraptions) and how that can introduce errors beyond 100 yards, please explain.
The only problem that I can see with my method would be related to ever-so-slight deviations of recoil from purely vertical while the bullet is still traveling down the barrel. And even then, having a perfectly square scope would only be an advantage when you had a level or plumb reference in the same field of view as your target, which almost never happens.
Let me explain that last paragraph. If recoil is not purely vertical and has a slight component to the side, that will tend to “hurl” the bullet off to the side and eventually hit off to the side of where you were aiming down range. The farther the target, the greater the sideways error. In practice I cannot imagine that I “cant” my rifle much more than a few degrees which would introduce exceedingly tiny errors down range, even at 400 yards. Perhaps more importantly, you are likely to “cant” your rifle a few degrees even when your scope is truly square to your rifle because your field of view will likely be unlevel and your eye will naturally level your reticle to the unlevel environment of your target.
Thus, I don’t see how a perfectly squared scope is critical in the real world.
Rifle cant makes a huge difference and it is one of the first things that new precision shooters need to work on. It is the reason why there are so many different scope/rifle leveling systems for precision shooting.
Sight height over bore axis is a critical measurement.
If your reticle is not level to the bore axis, every time you make a vertical change you are making a horizontal change as well, and vice versa. This makes accurate adjustments almost impossible.
By the way, I just ran the numbers with a Remington 5r in 308 shooting a 175 grain smk at 2600 feet per second and zeroed at 100 yards and shooting just four hundred yards away. If you are just five degrees off plumb, your bullet will land nine tenths of an inch away from where it would have if it was plumb. You’ve doubled inaccuracy of even the finest competition rifles.
jwtaylor, the more I learn about long distance percision, the more concern I get about breaking the bank (still saving up for a 308 win bolt) and making the time to practice. Thanks for sharing your experience.
Mr. Taylor,
Your example where a 5 degree “cant” would cause a bullet to hit 0.9 inches to the side at 400 yards illustrates my point: the amount of error is tiny, bordering on negligible. Even at 800 yards the error would be on the order of 2 inches. And at 800 yards, several other factors (such as Coriolis effect, spin drift, and unknown cross-winds) are probably going to dominate inaccuracy.
Even with a scope that is perfectly square (level/plumb) to the rifle, the only way that the shooter can hold that rifle-and-scope system level when shooting (to avoid having his/her bullet hit off to the side) is if there is a level or plumb reference in the field of view when shooting. And on top of that, that level or plumb reference in the field of view would have to be located extremely close to the cross-hairs in order for the shooter to rotate the rifle and align it to the reference with an error of one or two degrees.
Absent a level/plumb reference in the field of view and right next to the cross-hairs, the shooter has no reference and therefore could easily hold the rifle several degrees off from plumb at the time of the shot.
Final word: it doesn’t matter whether a scope is a few degrees off from square or if the shooter holds the rifle (with a perfectly squared scope) a few degrees off from level, the result either way is the bullet hitting a tiny bit to the side — apparently on the order of 1 inch at 400 yards. In the real world I think this is inescapable in all but a handful of circumstances.
Gotta agree with u_s. The 0.9″ difference due to the 5 degree cant is dwarfed by the 1.3″ change in point of impact from a 5mph crosswind increasing to 6mph.
Uncommon, at 800 yards it’s 3.2″. I don’t find that negligible at all. Yes, scope levels attach directly to the scope or the base of the receiver. They make a huge difference.
Again, that’s only a 5 degree cant. Out of 360 degrees. You probably have much more.
Again, if you don’t have your scope level, it’s almost completely impossible to make accurate adjustments for wind or elevation.
The difference between a 5mph crosswind and a 6mph crosswind is 5.9 inches at 800 yards.
Governor, exactly. We are adding even more error on top of that. Plus, with the scope out of level you will not be able to dial for wind in the first place. Every time you dialed for that 5 mile an hour or six mile an hour crosswind you would also be dialing up or down in elevation. Your scope out of level makes it hopeless.
Mr. Taylor,
You still have not addressed a hugely critical point: how does the shooter with a perfectly squared scope ensure that he/she is holding his/her rifle perfectly vertical (plumb) when squeezing the trigger?
Go to accuracy1st.com, click on products, and then scope levels. That’s the scope level I use on my scopes. JWTaylor is absolutely correct. For long range shooting the scope reticle needs to be plumb. Especially if dialing for elevation and wind is intended. If the scope is canted to the right the reticle will move down and to the left when elevation is dialed for. This will cause the aiming point to be up and to the right. If the scope is canted to the left the same thing will happen except the aiming point will be up and to the left instead. If dialing for wind instead of holding for wind just compounds the problem. The scope and rifle absolutely needs to be square/plumb to the fall of gravity since gravity is what is playing on the bullet after it leaves the barrel. Gravity force is up and down, the vertical line of the reticle needs to be on that same plane.
Uncommon, yes, I did. With the level attached to your scope or the receiver. That’s why they are standard equipment on most precision rifle set-ups.
Y’all, there’s no argument to be made here. This is some of the basics of long range/precision shooting. Shooting with the bubble is not new, it’s not “advanced”, it’s part of the basic set up every time you get behind the gun.
Now, playing with cant, intentionally causing cant, that IS advanced shooting. Todd Hodnet is a friggin wizard there.
Now, playing with cant, intentionally causing cant, that IS advanced shooting.
Once the scope, scope level, and rings/mount is level on the rifle, use the scope level to adjust out any cant that the natural hold of the rifle induces.
JWT, depends on what the intended use of the rifle is. If you’re serious about long range competition then yes, you want to eliminate any discrepancy no matter how small. But then you’re probably not doing a ‘redneck’ anything. On the other hand if you’re mounting a scope on a deer rifle you probably have no business shooting at game past 300 yards anyway and if you do you’ll probably be using a bullet drop reticle and then the only thing that matters is that the reticle is plumb.
He’s wrong about one thing, a true “redneck” wouldn’t have Torx, it would be Phillip’s head or even slotted. And before you holer too much, I was born in Virginia.
A stripped phillips head with a hack saw used to convert it to a slotted.
And, no duct tape in this method.
So a while back I needed to put a new scope on a new .30-06 bolt gun. Having none of the required specialized leveling widgets, I made use of a piece of exercise machinery. A pull-down bar for lifting weights. Took the handle off it and routed cables to create a pair of “V” shapes that I could lay the rifle within. This at one end of the house.
Which happened to be lined up with the back door, which I opened.
Which meant that I had a small opening thru the trees to the metal flashing at the corner of an office building roof some distance away. I moved the rifle and scope about until I was comfortable it was all square and level to the lines of the building edge. The bolt out of the gun, I peered down the bore and went back and forth to the scope until I figured it was darned close for my eye.
Later, well after midnight …..
I had just bought a laser in a .30-06 case, on sale at Cabelas. Put that in and put the bolt back in, and closed it up. Over a hundred yards I figured, I adjusted the crosshairs to where I thought they should be and that was that.
A couple of weekends later when I had the time to get out of town, I could easily hit clay pigeons set out between one and two hundred yards, no further adjustment.
Good ’nuff for lazy old me with limited budget for widgets, I figured.
Yep, lined up my scope with a wall edge down the hallway, worked well enough. Most shots out here are <300 M/Y so any errors are moot.
first i throw all the cardboard boxes in the garbage where theyre supposed to go then i just simply zoom the scope out enough so i can see the end of the pic rail in it and i put the bottom of the reticle in the middle of that
i shoot sub moa with that all the time
lets keep it simple
these things arent going into low earth orbit
I don’t know why all these “experts” keep pushing that scopes have to be level with the rifle. It just should be close.
The scope only has to be level with the world.
If the scope is a few degrees off of level from the rifle, you will never notice it out to a mile. Other more prominent factors will hide it. If the scope is not level to the world, then the error is noticeable.
I can mount a scope with none of this process and my system will shoot just as well as any.
I use Badger Ordnance Dead Level and a plum line. The dead level levels the mount or rings and the plum line levels the reticle. Before removing from the dead level install a scope level such as an Accuracy 1st (awesome scope level by the way) and never wonder if your scope is level when shooting again.
Plum should have been Plumb.
Here’s the true redneck way. Put de scope on de rifle, take dem boat down to de range. Shoot de target. Zero de scope. Go win a turky and call me in da mor orning. There is however a more scientific way of doing this. Find a clear area about 200 yards long. Park your car at one end of it and drive a stake in the ground at the other end leaving about four feet protruding from the earth. Now mount the rifle thru the window rolling it up and using the steering wheel to adjust castor and camber Alabama Chrome tape works well for securing the rifle in position. Hopefully you have had the foresight to park the car at the correct angle so that the barrel is pointing at the stake. Now taking 210 feet of very fine piano wire and inserting one end of it thru the barrel, then pulling it out thru the ejection port and poking it thru an empty shell casing that has the primer punched out then placing the casing in the chamber and securely wrapping the wire around the trigger guard, take the other end over to the stake being very careful not to kink the wire secure the wire to the stake and paint a two centimeter dot where the wire first makes contact with the stake. Now return to the car hopefully no one has stolen it or the rifle. Now whip out your micrometer and center the wire where it exits the barrel. We are almost done. Now go to the passenger side of the car and get in slide over to rifle and peer thru the scope if you are lucky the crosshairs will be centered on the white dot you painted on the stake. If not check for wind possibly blowing the stake one way or the other. If the horizontal hair is too high or low you may have to put air into the appropriate tires or let some out, or a combination of both. Now at this point if the crosshairs are centered on the spot on the stake and you have picked a safe place to set this up to begin with, you can remove the empty shell casing and wire from the rifle and insert a live round in the chamber and again making sure it is safe , proceed to kill the stake. If you only wound the stake just blame it on the wind. Should you miss the stake entirely and it hasn’t ran off you may want to go back to step one and make sure you followed each step precisely. Or just go get a beer and forget the whole thing and in the future learn how to use the iron sights correctly.
I align my scope cross hairs on the vertical edge of a door frame. Done.
You must live in a very very well built house that is brand new and hasn’t experienced settling of any kind.
It’s good to know that installing new scope rings doesn’t require a lot of complicated tools. I’d like to buy new ones for my gun because I’m working on restoring it. It’s already quite old and will need some new parts later on.
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