Where (and how) to locate a scope

by B.B. Pelletier

This post was requested by MCA, who has noticed some movement in his shot groups depending on where he places his face on the stock of his air rifle. This is a problem older than scope sights and was first addressed in early Army rifle marksmanship manuals of the 1870s.

The spot-weld
During World War II, marksmanship instructors taught soldiers about the “spot-weld.” The term was used to embed the notion that there is only one place on the stock for the head to be. [I recently saw this term called both a "stock weld" and a "cheek weld" on the Internet, but they mean the same thing.] That is important because of the relationship between the sighting eye and the sights. Parallax is the phenomenon that describes the apparent movement of near and far reference points due to different sighting angles. Big words for a simple concept.

Parallax
Hold up one finger at arm’s length and align it with a distant mark. Then close each eye separately and see if the finger moves in relation to the mark. It should appear to move when your non-master eye is open but your master eye is closed. Because your eyes are separated, they each see things from a different angle. That’s what enables you to judge distances, and it also demonstrates the concept of parallax.

The eye must remain in place!
If you move your sighting eye relative to the reticle of your scope, the reticle MAY appear to move on the target. I emphasize MAY because if there is zero parallax at the targeted range, there SHOULD be no movement. So, if you place your head on the stock differently each time you shoot, the reticle will be aimed at a slightly different point. That will affect your impact point. If you keep your head still for five shots but in a different place than when you sighted in, you will get a tighter group that has shifted from the initial aim point. If you move your head for each shot, your group will be much larger than it should be.

The solution is to find the best spot on the stock for your head to rest in order to see clearly through the scope, and ALWAYS place your head at that spot! That spot, which must NEVER change, is called your SPOT-WELD! Got it?

Whether your scope has parallax adjustments or not makes no difference if your head is always in the same spot. That cancels any parallax error.

Natural hold
Locate the natural hold by adjusting how you hold the gun until it feels natural. If you cannot see through the scope in that position, you need to move the scope until you can. That can mean relocating the scope at best, or new scope mounts (and sometimes a new scope to go with them) at the worst.

Once your hold feels natural and you can see through the scope, LEARN that hold and practice it until it becomes a habit! This is the reason that a one-gun shooter is often more accurate than someone who owns many guns. In the Army, they used to put masking tape on the stock so the soldier would remember where his cheek was supposed to go. Another technique was to grasp the wrist of the stock in a certain way, so your cheek was always pressed against the side of your hand.

However you do it, locating your shooting eye at the same point every time is a serious accuracy tip.

30 thoughts on “Where (and how) to locate a scope

  1. BB,

    for plinking I bought a low-cost gamo red-dot and realized it has tremendous parallax. I don´t think this is normal, maybe I tested at the wrong distance.

    For compensation the dot alwas has to be in the middle of the lens and fast target acquisition is impossible.

    Is this a problem of cheap lenses/mirrows or am I aiming at the wrong distance?

    Markus


  2. Markus,

    This is how ALL red dots work! You don’t have your sight mounted in the right place for you. Read today’s posting and reposition the sight until when you acquire it, the dot is centered.

    B.B.


  3. But I thought the relevance of a red-dot is the fast shot as long as the dot is on target, no matter where you are looking from. That´s why the mirror has such a concave geometry. After all I´m not sure about the distance to the target and from my eye to the dot.

    Markus


  4. Markus,

    No, the dot doesn’t work that way. Quick on target means because the dot is luminous, you acquire it sooner. Also the dot is much large than the intersection of two crosshairs. Also, a dot is faster to acquire than the intersection of two crosshairs because it is one thing – not two.

    But you do have to be centered in the same respect that an aperture sight can also be “fooled” if you don’t center the target in the hole.

    B.B.


  5. It would be like if the rifle is pointed an inch off the target but the dot is on the target the shot will still be an inch off reflections do not count. That’s why you sight in with the exact same hold and head placment if possible I would ad a bubble level it seems like something else that will “slow” you down but once you get used to it you will find the “speed” your looking for.

    Robert 1250




  6. sav300,

    PCPs are more powerful and easier to shoot accurately. That said, I shoot both, but PCPs are what I shoot the most.

    B.B.


  7. BB,

    I was reading Gaylord’s new article about PCP hand pumps. He says that the black grease on the pump is a special grease and if removed the pump will soon fail. Leading a person to believe that this is the only grease for pumps period. Any thing else will destroy the pump. Well my pump was getting dry so I emailed Hill. They said they sell pump grease but any pure silicone will be fine. This is a reoccuring problem with in the hobby, misinformation! I’m not talking about what pellet lube or pellets one guy opinion says is best compared to another, but directly opposed factual information. I’ve seen other examples from manufacturers. Sometimes the more you read, the more your confused!

    Jason


  8. BB,
    Which brand of PCP do you shoot? I am impressed with the condor and would love to be able to afford one(like thats going to happen). Anyways, I just thought I’d ask since I have to put down my old springer and buy somthin’ new.
    sav300


  9. Question:
    What is the difference between a Walther CP 99 pistol and the CP sport models?
    They look quite similar butsell for about a $100. difference.
    Thanks


  10. Jason,

    I read that article too, plus I own both a Hill and an FX pump. He’s right. The pump grease the FX uses is completely different than what’s on the Hill. In fact, My Hill has very little on it, but my FX has a gritty feeling black grease.

    I have also head that people who clean off the pump grease on their FX have suffered failures. Why would someone remove a lubricant the factory applied? That’s the question.

    My FX is several years old and the factory grease is still doing its job. I use it outdoors all the time and it doesn’t run off or wear off. It does collect down at the ends, but that’s where the O-rings are located, so I guess that’s a good thing.

    B.B.



  11. Walther CP99 pistols,

    The principal difference between the CP99 and the CP99 Compact is one gun is a pellet pistol while the other one is a BB pistol. The BB pistol is smoothbore, so the barrel is much cheaper. It also has a simple stick magazine that uses a simple blow-out process for firing.

    The pellet pistol has an intricate 8-shot rotary magazine with a pawl advance and positive indexing. Also the slide is made in two pieces and one moves back to allow loading the magazine. The BB pistol has a one-piece slide that is cheaper to make.

    That’s the reason for the $65 difference between the two guns.

    B.B.


  12. B.B.

    Could you please say which scope you use on your TalonSS? I’ve been changing scopes around on mine and am not yet completely happy with the scope length and sight picture.

    By the way, thanks immensely for your work on this blog. Writing a daily column is a huge chore, and the knowledge and information you so freely give is a huge benefit to your readers. I read you every day.


  13. Markus,

    I too find red dot scopes frustrating. One has to be very careful to get the dot lined up the same within the scope tube each time. Additionally, the dot itself is four or so MOA and thus can be bigger than the target you want to hit if it is at a distance. Once I learned their limitations however I find that red dots have their place.

    ELK


  14. Pcp’s are the most advanced airguns.I wold love to get one but I can’t see spending $400 – $600 and then spending another $200 on accessories that are necessary to use for a pcp.



  15. Jed,

    Yes, the cost is a factor. Once you get over that hurdle, though, a whole world of airgunning opens up.

    B.B.


  16. CP99/CPsport,

    The difference between CP99 and CP sport is, CP99 has Single/double action and the slide is also made of metal. The CP sport is double action only and the slide is made of plastic, and thus is the reason why the CPSport is cheaper than the CP99. Performance wise, I believe they are the same since they use the same barrel.


  17. Another note on the CPSport and CP99.

    CPSport, even though it’s cheaper, has adjustable rear sights for windage with tactical white dots on the sights.

    CP99′s sights are fixed and cannot be adjusted. You might be able to purchase adjustable sights as an accessories, but I’m not certain about it.



  18. Sorry for the confusion, I thought the original question was between the CP99 and CPSport.
    CP99 compact is another gun that shoots BBs. CP99 and CPSport are both made in germany while CP99 Compact is made in Japan. They’re all umarex though.

    Currently, there’s three models that I’m aware of… CP99, CPSport, CP99 Compact.


  19. BB,

    I bought my pump used so I don’t know if the person that sold it to me removed the grease before I bought it, but I do know it needed lube. Thanks for clarifying the situation.

    Jason


  20. Jason,

    I read somewhere that someone once used Beeman Laser Lube on their pump, but I don’t know where to get it anymore. I have no idea what FX uses.

    B.B.


  21. If you have to place your cheek in the same place every time on a rifle, what happens with a pistol with a scope? My guess is that one would have to practice a LOT to make sure the gun was exactly the same distance, height, etc. EVERY time. I wonder if it is possible to get BETTER accuracy with a scope on a pistol.

    Michael



  22. Here’s one of those Rookie questions I warned would be coming yesterday. :)

    When shooting with a scoped rifle is it preferred to keep both eyes open, or close your non-dominant eye (the one looking through the scope).

    I’ve got some experience in practical shooting where I’m either using iron sights on a pistol or an Eotech Holosight on a carbine. For this I’m used to keeping both eyes open, where you want fast target acquisition and precision isn’t as important.

    Just curious if there’s any reason to do either/or when using a scope.

    Thanks!

    Ash




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