XS Sights® Frequently Asked Questions:
1. Big Dot or Standard Dot?
- Big Dot or Standard Dot?
- Is it OK to use a sight pusher to install XS sights?
- What is and how do I fit a dovetail?
- AR-15/M-16 - Rear Sight Elevation Shifts and the need for a Same Plane Aperture Sight
- Sighting in AR’s with Tritium front sights
- With a Ghost Ring Aperture rear sight can I use my original front sight?
- Cowboy Express Sights-- Are these SASS legal?
- What are these plastic pieces in my package and/or how do I use the test posts?
- How do I adjust my Ghost Ring Aperture sight up/down/right/left?
- I have installed a set of sights on my rifle and cannot get it to sight in. What do I need to do?
- What is Tritium? What is “Half Life”? Why do you have only the green color?
- How can I tell if my Kahr has the new style sight cuts?
- I want my express rear sight to have tritium but you don't offer it, why?
- I have a Remington 870 Tactical with the XS white dot front sight and I want to get a tritium front sight, what is the part number?
- When will you have a Big Dot front sight for the Ruger LCR?
- Can the Angle Eject Scout Mount be fitted to a Top Eject Winchester 94?
- What installation tools does XS recommend?
With so many selections how do you pick the one that is best for you? First off let’s go over the basics...
2. Is it OK to use a sight pusher to install XS sights?
These situations for the most part occur at 21 feet or less, usually a lot less. Department of Justice annual reports state that 90% of police shootings happen at this range or less. A study of shootings over 100 years in New York City have more than 90% of shootings at 10 feet or less. The DOJ study includes figures from sheriffs departments, highway troopers, and Border Patrol. Encounters by these agencies can occur at longer ranges (more than 21 feet but less than 25 yards) so they will skew the average range figure a bit.
In the “when” category, about the only common denominator was that light conditions were less than adequate. In our own research we found there was a gap in the visibility of most sights on handguns. Plain black sights rely on having sufficient ambient light to see them against a contrasting background. Such target sights are black and meant to be aligned against the white of the target paper and held in reference below the round bull of the target. This is fine until the background becomes the blue, red, plaid, etc of clothing and then the sight blends in to the point where it might as well be invisible. Contrasting inserts help but are generally too small to be readily seen. Night sights were a big help in low light to no light situations. But since the tritium vials are a weak source of light it does not take much ambient light overpower them leaving you unable to adequately see them in the half light to low light realm. And because they are installed in the same place where a contrasting color insert might be, they remove the ambient light reflector that you might have used in this half to low light range.
What happens that is so different.?
If people were only attacked by static pieces of cardboard, then we wouldn’t build our sights the way we have. The same can be said if all shooting situations gave you a walk through before hand and if everybody involved was clearly marked as to whether they were SHOOT or NO-SHOOT people. But they don’t so you’ll have to have to make a whole bunch of decisions, in the moment and on the fly. What you’ll need is information. Information like body language, intent in the eyes, movement of the hands, and/or are there threats from other directions? This means that your eyes will be bouncing all over everywhere except on your sights. Only if a point is reached where deadly force is required, will you need sights and the time it takes for your eye to shift back to find them and get them on target is critical. The stress reactions by your own body are working against you quickly finding your sights. Proof that you can easily miss a man-sized object at 3 feet is found by looking at police qualifying scores versus percentage of rounds that hit in actual gunfights. Most LE Agencies require that officers qualifying score is at least 70% of the possible total, while the average number of rounds that actually impact is less than 15% of those fired. If this isn’t a clear indication that what works well on a target range under target conditions is next to useless under tactical conditions I don’t know what is.
What we offer.
Shallow “V” express rear notch. This eliminates the billboard found on each side of a standard notch rear sight. You have better access to the front sight and it is impossible to hide the front sight behind the rear sight. The “V” is not a bull’s-eye sight and you will not get the same tiny groups that you can get with such sights. You will get plenty of tactical accuracy and not take forever to find and align the sights in doing so. The vertical bar in our sight is readily distinguished from the front dot. This eliminates any confusion as to which dot is the front sight. Available in the 24/7Express series our most popular sights can be had with this bar as a tritium element.
Big white dot with tritium (Big Dot Tritium/BDT). The bigger sight is easier for your eye to pick up. Easier to see when your focus is out beyond the front sight locked on the possible threat. The large white area is huge reflector of ambient light and will be seen way on down into the very low light range. At that point the tritium vial in the center of the dot comes into play and begins to take over the sight reference duties giving you a positive front sight reference on down into the no light spectrum.
A better Point of Aim (POA) / Point of Impact (POI) system. When your eye is making that shift in focus it will lock onto the brightest thing first. The brightest part of the dot is the center. Placing that over the desired point of impact is a natural reaction. From 15 yards on in our POA/POI is center of the dot. As the range increases and you have more time for a refined sight picture we take advantage of your pistols ballistics. Bullets start out below line of sight and the barrel angle is such that they rise to line of sight. By having the under 15 yards POA/POI at the center of our dot then as the range increases to 25 yards the bullets flight will take it to near the top edge of the front sight. Now you have the best of both worlds. A stress sight picture that is quick and easy to find and index on the target and a more precise POA/POI when you need it at longer ranges.
The Standard Dot Tritium. We have it around because no matter how logical and sound the Big Dot system is you just can’t convince everyone as to its advantages or that you really can shoot accurately with it. The Standard Dot Tritium gives them a better front sight so they will have some improvement. We sell quite a few of them to the gamers who want a better front sight but shoot in a world where the targets are generally static and clearly marked as to which ones are hostile and which ones are not.
3. What is and how do I fit a dovetail?
Sight pushers are a handy tool to easily move an already installed sight the small amount needed to regulate windage correctly. Sight pushers are a simple screw jack which has a very large mechanical advantage and can apply a great deal of force on a small area with an easy twist of the fingers. It is difficult to “feel” how a sight is going into the dovetail.
Other maker’s sights have been manufactured to allow them to be installed with a sight pusher. One version will have a hollow area under them to allow the sight to compress and go on into the dovetail. Other manufacturers will build the sights out of soft steel so the excess material will readily shave off as the sight goes into the dovetail.
We don’t think having sights made from malleable steel is a good thing so we build our sights from solid bar stock. Solid steel does not readily compress or bend. They are designed to be fitted in the traditional manner. If you use a sight pusher to install our sights in a dovetail without checking and altering the sight to correctly fit the slide dovetail you will most likely damage or break the sight. The sight will start in the dovetail due to the chamfered edges and then the power of the sight pusher will bend or break the sight when it binds up unless it is fitted properly.
See FAQ # 3, below, for dovetail fitting instructions.
Dovetails are the primary method of installing sights on handguns and one of the more common ways rifle sights are installed...
4. AR-15/M-16 - Rear Sight Elevation Shifts and the need for a Same Plane Aperture Sight
A dovetail is an angled cut (female dovetail) into which a similarly shaped and sized piece (male dovetail) fits into. The fit is an “interference” type fit. Simply put it is a 1.001 inch peg in a 1 inch hole.
Any mass manufactured part will have minor variations of dimensions. These variations are called “tolerances” and have upper and lower limits. While today’s computer controlled machining centers can produce parts with very small tolerances, there are still minor variations that must be adjusted for. Our sights are made on the large end of the tolerance range to allow them to be fitted to the particular dovetail on your pistol or rifle.
Dovetail specifications are as follows:
Theoretical point to point: This is the large dimension of the dovetail taken at where the angled points meet the bottom of the dovetail. The reason they are referred to as “theoretical” is that such fine points are difficult to achieve and easily roll off (male) or are not cut due to wear of the cutter points (female). The male portion of the dovetail is normally made with this point having a chamfered edge to allow it to more easily fit the dovetail cut. That is why if you measure this portion of a dovetail you come up with a dimension that is smaller than what the specification list.
Angle: This angle is measured at one of the points of the dovetail. The range is anywhere from 45 to 75 degrees. Some of the more common angles are 60, 65, and 75 degrees.
Depth of dovetail cut: This depth which is measured in thousandths must be controlled due to the over hang of the sight body (front and rear) over the dovetail section. Cut to shallow and a gap between the bottom of the sight and the barrel/slide/frame appears which is not cosmetically pleasing. Cut to deep and you will have to relieve the overhung portion of the sight so it will fit into the dovetail. Sometimes the front sight will snap of the dovetail section due to the weakening of the sight and the additional stress created by this situation.
Taper: Old style dovetails where cut on a tapered angle so that one side was larger than the other. This allowed for easier fitting unless the sight needed to be moved back out of the dovetail, which could leave it with a too loose fit.
Check out the dovetail installation video for more help.
As originally designed the AR-15/M-16 sight system adjusts for windage at the rear assembly and for elevation in the front to zero the rifle to the individual shooter...
5. Sighting in AR’s with Tritium front sights
To obtain the ballistic adjustment needed for longer range shooting the original rear sight had one aperture higher than the other. While this system would not give the shooter an exact elevation adjustment for a specific range, it would under battle conditions put the bullet close enough for government work so to speak.
The new A2 rifles and carbines employ a rear sight system that includes a range cam to allow the shooter to more precisely adjust the ballistic arc to their needs. This system eliminated the need for an elevation shift between the large close quarters aperture and the smaller long-range aperture. However the aperture shift is still with us today.
Comparing some of the rear sights available today there appears to be 3 variations available. The 1st style (and oldest) has a .014 offset. This gives a 2.52 inch shift in point of impact at 100 yards between the two apertures. The 2nd style has a .017 offset, which shifts point of impact 3.06 inches at 100 yards. The 3rd style has a .024 offset giving a 4.36 inch shift in P.O.I.
All of the points of impact shifts shown above are for the standard barrel AR-15/M-16 that has a sight radius of 20 inches. The shorter sight radius (14.5 inches) of the M4 carbine and weapons of similar configuration increase the amount of point of impact shift. The shifts for these shorter sight radius weapons are 3.48, 4.25, 5.96 inches respectively.
The only reason for the various shifts would be for changes in the ammunition used by the military over the course of this weapons employment.
Most people are completely unaware of this elevation change that occurs when the aperture is shifted from one to the other. They just figure that their rifle is doing something strange.
Our aperture sight for this weapon has both the large and small apertures on the same plane so there is no difference in the point of impact when you shift from one to the other. We have also offset one of the apertures by .007 to make up for the sideways movement of the aperture on the windage screw as it pivots.
By installing our same plane rear aperture you now can sight in your rifle using the smaller aperture and shift back and forth between the two apertures as your light and range needs change without having to do mental gymnastics to know where your bullets impact will be.
Check out the AR-15/M-16 installation video for more help.
The original round front sight of the AR-15/M-16 rifle was a round post that used one of 5 detent notches for elevation...
The thread pitch of the screw is such that a 1/5th rotation of the post moved point of impact approximately 1 inch at 100 yards.
When the round post was changed out in favor of a square post the number of detent notches was correspondingly reduced to 4. The fact that the reduced number of notches increased the amount of movement from 1 to 1.25 was more than compensated by the better front sight presentation.
Our 24/7 Stripe or Dot front sights require a full 360-degree rotation to present the face correctly to the shooter. This translates to a 5 or 7-inch change in point of impact per revolution, depending whether you have a standard or short barrel configuration sight radius. At first this may appear to cause problems but in reality that will not be the case. If you are 5 inches from desired point of impact then the new setting will bring you exactly on line. The furthest out you will be is half of the sight shift, meaning 2.5 to 3.5 inches.
The majority of the rifles and carbines made today have the new A2 style rear sight assembly. The range cam can be disengaged from the elevation mechanism so the 1-minute elevation per click may be employed to correct any remaining problems. The Allen screw to do this can be accessed through that large hole in the rear sight assembly that is just in front of the aperture (now you know what the heck that hole is for).
Even without this ability the fact that the groups most of these rifles generate at this distance are in the 2 to 3 M.O.A. size will allow you to place the zero somewhere between the center and the top edge of the dot at 40 yards..
You must also consider the fact that 100 +yard shots are at the far end of the spectrum in which these rifles are employed by most people and Law Enforcement personnel. When used as a patrol rifle by Law Enforcement personnel it is to supplement their handgun (ranges contact to 15 yards) or extend their zone beyond that realm (25-75 yards). At 50 yards the problem of sight shift is halved and at 25 yards it is now back in the 1.25” (1.75” for shorties) inch per revolution range.
Recommended sight in range is 40 yards.
With Dot type front sights, adjust so that the center of the dot is as near the point of impact as possible. As the range increases the bullet’s arc will cause it to rise to near the top edge of the dot at the 120 to 150-yard point (depending on ammunition). Beyond that point the bullet’s arc will bring it back down to center of the dot at approximately 250 yards.
Check out the AR-15/M-16 installation video for more help.
6. With a Ghost Ring Aperture rear sight can I use my original front sight?
The sight line used by the Ghost Ring Aperture is generally taller than the one used by the barrel-mounted sights...
A taller front must be used so point of impact stays the same.
See FAQ # 8 for use of test posts to determine front sight height.
See FAQ # 9 for precise sight-in instructions.
7. Cowboy Express Sights-- Are these SASS legal?
The SHOOTERS HANDBOOK, the R.O. MANUAL and the SASS office were consulted during the design phase. The prototypes were reviewed by Hipshot SASS#7 at SHOT Show 2005 to ensure that our sights complied with SASS regulations. The sights were also reviewed by a group of Territorial Governors at 2005 End Of Trail and were found to be within SASS regulations.
What do these sights offer over other sights?
The bigger, bolder front sight is faster to pick up over other front sights. The ivory white bead is much better protected compared to other bead sights, virtually eliminating bead breakage.
The rear express sight gives the shooter greater downrange visibility compared to other barrel mounted sights allowing faster initial target acquisition and target-to-target transitions.
As big as these sights are, are they accurate?
If Cowboy Action Shooting took place at several hundred yards instead of several hundred feet their size might be a factor, but at any normal range shooters will be surprised at the level of accuracy that can be achieved with these sights.
8. What are these plastic pieces in my package and/or how do I use the test posts?
Our sight sets come with what our shooting trials have determined to be the most commonly used front sight height for each particular model and caliber.
In 2019, XS decided to remove many of the test posts from our front and rear sight sets. If you'd like one, please contact us and we'll be happy to send it! Otherwise, if zeroing issues occur, XS will replace the front sight under our No Questions Asked Warranty.
Variations from this standard can occur either due to manufacturing tolerances or more commonly ammo/shooter variations. The included test posts allow you to verify that the front sight will work for your rifle, or what height will work for your particular rifle/ammo/shooter combination.
These plastic test posts should be used BEFORE the metal sight is installed. The shorter one duplicates the height of the metal front sight and is the one you should use first.
The factory setting on our rear sight should be 3 full turns (360 degrees) up from bottoming out the aperture. The rifle should sight in within 3 full turns up or 2 full turns down from this factory setting position.
If you have to adjust the rear sight more than 3 full turns up from this position, then a shorter front sight is needed. Return the sight to the factory setting and then remove one segment from the top of the test post and re-shoot. Each segment represents a sight height we make and will shift point of impact 5-8 inches at 100 yards depending of your sight radius. Remove segments as needed until you can zero the rifle within the specified sight adjustment range.
If you have adjusted the aperture 2 full turns down and the point of impact is still high then a taller front is required. Reset the sight and install the taller test post. Remove segments as needed to bring point of impact up to where the sight will adjust within the recommended range.
Once the correct height has been determined contact us and we will exchange the unfitted front sight for one of the proper height. Our toll free number is 1-888-744-4880.
See FAQ # 9, below, for precise sight-in instructions.
9. How do I adjust my Ghost Ring Aperture sight up/down/right/left?
To sight in your Ghost Ring Aperture sight you should know the following...
The stem of the aperture is threaded, and by turning the aperture ½ revolution you will move point of impact approximately 1 inch at 100 yards.
The windage screws will shift point of impact approximately 1 inch at 100 yards per ¼ revolution.
Elevation Example: At 100 yards and the bullet impact is 4 inches low. Loosen one of the windage screws a full turn to allow the aperture to then be turned 4 half turns up (counter-clockwise). Then re-tighten the same windage screw. Remember you always move the rear sight in the same direction you wish the bullet impact to go. This will put you within a ½ inch of the desired point of impact.
Windage Example: This same rifle is 3 inches off to the right at 100 yards. Loosen the left windage screw ¾ of a turn and tighten the right windage screw to move the aperture and the group to the left.
NOTE: Rear sights are always moved in the direction you wish the bullet impact to go. If you raise the aperture the impact will come up.
Front sights are moved in the opposite direction. To raise the point of impact the front sight must be lower.
See FAQ # 8 for use of test posts to determine front sight height.
10. I have installed a set of sights on my rifle and cannot get it to sight in. What do I need to do?
Our sight set front and rear selections are made after we have actually shot that particular rifle at the range and verified the zero...
The set then will work for more than 90% of the people/rifle combinations out there. If you are having trouble sighting in your sight set, while it might be a mechanical problem it might also be how you are trying to use the sights that is the source of the problem. Here is a list of common shooter errors.
It is called a “Ghost Ring Aperture” sight because the rear aperture is supposed to blur to the point that it is a ghost image in your eye. The aperture itself is not important. The beam of light coming through it is what your eye acts on.
Do Not Try To Center The Front Sight In The Aperture!!!! Your eye is attracted to bright light. The brightest portion of the beam of light coming through the aperture is the very center. You should concentrate your focus on the tip of the front sight and it’s relationship to the target. If you try to center the front sight you will be everywhere but the center. Keep your eye on the tip of the front sight and the target and let nature do the rest.
I am shooting way high and the sight is bottomed out!! This normally occurs with shooters who have used regular aperture sights before but not Ghost Ring style sights. Most aperture sights have disc in them with a small sight hole through it. The hole is so small that sometimes target shooters will fire on the wrong target because they can see only the bull’s-eye of the target. A Ghost Ring Aperture gives you a wide field of view. You will see all the front sight, some of the ramp or barrel and a whole lot more. This confounds some shooters who try to see just the blade of the front sight. Doing this sets the front sight low in the aperture and then when they place the tip of the front sight on target it causes the bullet impact to be way high. Once again concentrate on the tip of the front sight and don’t worry about what else you see in the aperture unless it is the eight point buck standing just to the left of the six point you are aiming at!
Lastly, sometimes there are shooter/ammo/range/gun combinations that require a different front sight than comes in the set. If that is the case use the test post provided or call toll free 1-888-744-4880 and ask for some test posts to be sent to you. Using them you can determine what is the correct sight height for your situation.
See FAQ # 8 for use of test posts to determine front sight height.
See FAQ # 9 for precise sight-in instructions.
11. What is Tritium? What is “Half Life”? Why do you have only the green color?
Welcome to XS Sight Systems Science 101...
Tritium is a trace element naturally present in the air your breath. Tritium is hydrogen plus two extra neutrons. Hydrogen as most people know has 1 hydrogen isotope, 1 proton, and no neutrons. By adding 2 neutrons to basic hydrogen you create Hydrogen3 or Tritium. The molecular structure is unstable and decays. In this decay process it throws off Beta Particles. When these Beta Particles collide with the phosphor coating on the inside of the glass tube the phosphor glows.
The term “half-life” refers to this decay process and how long the tritium vial will glow. The half-life time is how long it takes for the tritium to be half as bright as it was when new. After that point the speed of decay increases the vial brightness dies.
The color of the Tritium vial depends on the material used to coat the inside of the tube. Green Tritium vials are the brightest of all the Tritium colors. Even so they are rather weak light sources. Surprisingly small amounts of ambient light will overpower the Tritium creating a usage gap at the half to low light point of light levels. That is one of the reasons we have such a large white dot. The dot reflects any ambient light present so you have full sighting ability under any light conditions.
We chose a bar and a dot because having three green Tritium fireflies out in front of you can slow your response while you decide which of them is the front sight.
Some companies try to solve this dilemma by using a different color Tritium for the front and rear sight. While this helps some, it creates addition difficulties since all the other Tritium colors are less bright than the green.
We retain the brightest Tritium color and by utilizing a vertical bar for the rear, the front sight is readily discernable from the rear so there is no loss of time in indexing the sights on the target.
12. How can I tell if my Kahr has the new style sight cuts?
13. I want my express rear sight to have tritium but you don't offer it, why?
The short answer is we can't always have tritium in the rear sight of some sights because of size issues...
The tritium vials not only have to have a certain size, but also must have a certain amount of material around them. These vials are regulated by the Nuclear Regulatory Commission and they set the guidelines. The size of these lamps is the major factor in determining if sights can house a tritium lamp.
Because we as sight makers have to live with the sight cuts that are on each different make & model, we often have to make choices. In many cases if we make a rear sight tall enough to house a tritium vial, we would also have to make the front sight so tall that it would create holster fit issues. We never thought it was smart engineering to build defensive carry sights that then wouldn't allow you to use common carry holsters. If shorter lamps become available to us, then we would offer rear sights with tritium.
That however does not mean you have a useless rear sight. You have to remember one of the big reasons why we as a sight maker exist, and that is that a big chunk of gun uses occur at mid to low light levels. Under these conditions it is too bright to see the tritium very well yet it is too dark to see a plain black blade. The big white dot reflects the ambient light so you can see something & use it for your front sight index. This applies not only to the front sight but the rear sight as well.
Something that goes unrecognized is the simple fact that as light levels drop, so does the distance you can see to ID & engage a threat. At light levels where you can no longer see just the white stripe, you are down to mere feet. At theses distances a rear sight index is fairly redundant and all you should be doing is placing the front sight COM (center of mass) and not jerking the trigger.
Tritium in the rear sight is nice if you can get it, but it is NOT an absolute must have to have a very effective set of fighting sights.
14. I have a Remington 870 Tactical with the XS white dot front sight and I want to get a tritium front sight, what is the part number?
It is one of 4 possible part numbers...
Huh? Yup, four! .350"-.400"-.450"-.500".
Shotguns are variable beasts, what height zeros shotgun "A" may not work on shotgun "B" even though they are but one serial number apart. Add to this confusion, the ammo they use at the factory for zeroing may have considerably different ballistics than the ammo you have chosen to use. We have seen in some cases up to 14"" difference in point of impact at 25 yards between two makes of slugs.
So, the first thing you must do is shoot the gun with the ammo of your choice and see if it will zero for you. If it does, then we need to know how tall the front sight in your gun is. Height is measured from the top of the blade to the bottom of the dovetail in thousandths of an inch to the nearest .005" and compare it with the numbers listed above.
If it doesn't, we still need to know how tall the original front sight is. With that info and how far off from point of aim the point of impact is AND the distance the group was fired at, we can figure out what sort of height change is needed to bring point of impact to point of aim.
The sights are $71 each. Call the toll free order line 1-888-744-4880 to get one once you know the above needed information and we will be happy to get a tritium sight (of the correct height) headed your way.
15. When will you have a Big Dot front sight for the Ruger LCR?
Sorry, this one isn't going to happen...
In our developmental testing, we found that the tiny rear sight notch just didn't provide enough of a rear sight reference to allow a Big Dot to work properly. Our test shooters were reporting that at least half of them couldn't achieve decent accuracy with the Big Dot prototypes on the LCR which was very odd since these shooters were getting great results on some S&W snub nose "J" frame projects we were working on a the same time. In checking over the LCRs we found nothing wrong with them, but that the rear sight notch in the frame was shallower than the rear sight found on the S&W "J"s. It provided more than enough reference to allow a Standard Dot to work well, just not the Big Dot. There isn't an easy way to improve the rear notch so we are left only being able to offer the Standard Dot. While it hasn't got the speed or acquisition that the Big Dot has, it is still a huge improvement over the factory plain black blade.
16. Can the Angle Eject Scout Mount be fitted to a Top Eject Winchester 94?
The AE Scout Mount will fit if 2 criteria are met.
First, the center of the rear sight dovetail slot must be within a certain range of the barrel receiver junction line. The mount will fit if the center is within a range of 3.8" to 4.0" of that junction.
Second, you must be willing to have the 2 required screw holes (#6-48) drilled & tapped into the front receiver bridge in the manner the AE models are drilled. The mount itself is used as a layout template for actual screw hole locations.
If these are met, then you can install our mount on your rifle.
17. What Installation tools does XS Recommend?
There are a lot of good options, but here are a few things that we find especially useful:
60° Dovetail Standard Slot Sight Base File (Brownells 080-648-160)
65° Dovetail Slot Sight Base File (Brownells 080-648-165)