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Accessories Crosman Precision Diopter Sight System: Part 2

Crosman Precision Diopter Sight System: Part 2

Crosman sight system
The Crosman Precision Diopter Sight System.

Part 1

This report covers:

  • No cant
  • The test
  • Cocking
  • Sight in
  • One and only group
  • Discussion
  • Summary

Today I mount the Crosman Precision Diopter Sight System on the Crosman Challenger PCP 2009 and sight it in, in preparation for the accuracy test. I know the Challenger PCP 2009 is accurate, but how will it respond to this purpose-built sighting system?

It’s been two years since I last tested the Challenger 2009 and I had forgotten many of its characteristics. For starters, it is very quiet. My cat, Dale Evans, left the room when she saw I was preparing to shoot. She came back in half an hour later complaining that she couldn’t hear the shots, and how was she supposed to protest if she wasn’t aware of what I was doing? This air rifle is quiet. I wish I had recorded the discharge sound but since I didn’t I will guess it was around 81 or 82 decibels.

Challenger with sights
Crosman Challenger 2009 with the new The Crosman Precision Diopter Sight System.

I mounted the new sights and then I put the rubber eye cup on the rear sight. With that in place I don’t need the blinder to keep both eyes open. The cup makes the rear peephole very bright and easy to see. Without it the blinder is necessary for me.

Challenger rear sight detail
The only thing I did extra was to install the rubber eye cup that makes the rear peephole extremely clear and sharp.

Someone asked what the diameter of the rear sight tube is, so I measured it for you. It’s 0.940-inches in diameter.

No cant

I’m testing the new front sight with the 3.8 mm aperture up front. This is the one that sits square in the sight. There is no attempt to cant the sights today.

Challenger front sight detail
The Challenger PCP has a long dovetail that allows you to position the front sight wherever you want — on the dovetail. I put it at the end to get the longest separation between the front and rear sight.

The test

This is not an accuracy test. I just want to sight in the new sight system so I can do an accuracy test. Today also allows me to re-familarize myself with the Challenger PCP. I found the two-stage trigger is quite positive with just the hint of creep in stage two. I can use it quite well, plus it meets the NRA/ Civilian Marksmanship Program requirements for a trigger for junior marksmen. Unlike precision rifles (the CMP/NRA term for world-class 10 meter rifles) that have no trigger-pull requirements, the triggers on rifles used by junior marksmen must break at no less than 1.5 lbs. (680.4 grams). The trigger on this rifle pulls 15 ounces in stage one and breaks at 1 pound 8.7 ounces. That’s about as perfect as things can get.

I shot only the Qiang Yuan Training pellet today, because back in July 2020 it was the most accurate pellet. It seemed the best way to proceed.

I sighted in and then shot a single five-shot group off the sandbag rest with the rifle rested directly on the bag.


The Challenger has a T handle that pulls straight back to cock the striker and move the bolt back out of the way. I find the rifle very easy to cock and load. The FWB 600 is easier to cock and pump, but to do it I have to pick it up off the sandbags. I don’t have to move this one to do anything.

Sight in

Okay I have replaced the original sights with these new ones — both front and rear. Is the rifle anywhere near the target? Because of that I went up to 12 feet and shot offhand. The first shot went into the bull I aimed at. The shot was low and a little to the right.

I love that Crosman has marked the sight adjustment knobs with the direction the shots have to move instead of the backwards German way. No making mistakes here, plus there are index scales to watch where the sights move.

Knowing that the rifle was on target at 12 feet, I backed up to 10 meters and rested the rifle on the sandbag. Shot two cut shot one a little higher which I expected. I adjusted the rear sight four clicks up and three to the left. For some reason the next shot seemed to go into the same group so I adjusted the rear sight up and right twice as many clicks this time. The next shot was a 10. Time to shoot a group.

Build a Custom Airgun

One and only group

Okay, the next five shots were fired without checking the target through the spotting scope — which you now know is a pair of MeoStar binoculars. Back in 2020 this rifle put five of these pellets into 0.097-inches at 10 meters. That was before the silver Chukram comparison coin existed for groups smaller than one-tenth-inch.

Today I put 5 of there Qiang Yuan Training pellets into a group that measures 0.121-inches between centers at 10 meters. It’s larger than the group from two years ago, but not that much. When groups get this small any error in measurement throws things way out of whack.

Challenger Chinese Training group
Today with the new sights the Crosman Challenger PCP put five Qiang Yuan Training pellets into a 0.121-inch group at 10 meters.


I have to say I think the image through the new sights looks sharper and clearer than the image through the old sights — the ones that came standard on the Challenger. I used the same 3.8mm front aperture that the old sights used, but in the new sights the bull looked smaller with more white space around it inside the aperture. No doubt that was because of the rubber eye cup making the rear peephole brighter.

The new sights adjust crisply and the scales on the sight body tell which way the adjustment was made. The bars in the front sight insert that was used for today’s test allowed me to level the rifle by lining up with the bullseyes on the rest of the target.

I don’t know if I will even test the canting option, as the rifle seems to work well when it’s truly level. Canting would be for when the rifle is hand held.


This was just a quick little test to see if the new sights are as good as the old ones or perhaps better. I think they are at least as good. Would I spend the money to change over to them? Nope. But if I were buying a new Challenger PCP — the one that only Crosman seems to be selling at present — I would want these sights to be on it.

31 thoughts on “Crosman Precision Diopter Sight System: Part 2”

  1. BB,

    From the looks of it the rear sight requires a flat topped dovetail rail. It doesn’t look too be compatible with most springers on the market. I still cannot imagine the rear cant adjustment. How does one cant a circle? Is there a visual reference that can be seen while looking through the rear sight that can tell you if you are canted?


    • Siraniko,

      The lines on the tube of the rear sight are the reference for the amount of cant. They are the same as the lines on the front sight that the sight inserts line up with.

      You don’t see the cant when you shoulder the rifle. It just fits correctly so the sights seem level.

      This canting of the rear sight seems to be a confusing issue. I think it’s overrated and I wish I hadn’t brought it up, because as you say, a round hole cannot be canted.


      • If you do not cant the rear sight to match the front, the elevation and windage adjustments will be off axis and much more difficult to adjust the pellet strike on the target.

          • Shootski

            Cant is certainly misunderstood, but, in precision shooting,, where one shoots at a prescribed distance, it is much easier to understand. I was taught that to be repeatably accurate, one must have a repeatable hold. In order to do that one finds their “natural point of aim”. For most of us, that means to position ourself comfortably and then look through the sight or sights. If you are pointing at the ten ring you are halfway there.

            Close the eyes for a few seconds and then open them, and without moving anything, see where on the target your sights are fixed,, then move your body,, not your arms or hands to correct that. Repeat as many times as needed for the sight to always be on the ten dot when you open your eyes.

            When I was shooting in competition, it was my practice to reposition three times per target sheet. Once for each vertical row of targets. I would change my elevation with my breath, pausing my breathing when the sights were aligned and puling the trigger within that pause.

            Once accomplished, you can look at the cross bar of the front sight to see if it is perfectly horizontal as compared to the target. If it isn’t, then you are shooting with a cant. Do you try to correct for that,,, of course not. The only affect you notice is that you will be adjusting your sights a bit differently. For example, if you should need to adjust your POI to the 11 o’clock direction,, you may only have to change the elevation and not both the elevation and windage.
            The ability to change the cant of the rear sight is simply so that you can make the sight adjustments the way you are accustomed to doing.

            It becomes important when shooting at varying distances,, but for 10 meter shooting,,it really isn’t very important beyond understanding the difference in adjusting the sights.


        • Exactly.
          What a person is rotating is the up down adjustment to be true to the vertical and horizontal of the front sight or scope cross hairs. If you don’t rotate the rear sight your clicks on your rear sight adjustment won’t move true up and down or left or right.

          And honestly I need more elevation hold over or under at different distances than I do with my windage or canting the gun. Out to 50 yards if I have a gun that will shoot 1/2 inch groups at 50 yards holding the gun without can’t. I might get a 1 inch group at 50 yards canting the gun. So if I’m plinking or shooting a ground hog at that distance I’m ok with the 1 inch canted group.

          I think the main thing is to be aware of what cant and holdover is at different distances with the gun you shoot and how you are using that gun for shooting. And for me hold over or under at different distances is more concern than the left or right with cant.

  2. BB-

    Champion’s Choice, of LaVergne, TN, has the new Crosman Challenger in stock at $650..

    Regarding canting the rifle. This can be effective in order to let the rifle fit the shooter best when in the shooting position. Front and rear sights then need to be adjusted to compensate for the shooter/rifle. In other words- the shooter/rifle is tilted or not plumb to the vertical, but the sights are plumb to vertical. This allows the sight’s windage and elevation adjustments to move the projectile impact correctly on target. It is imperative to note that a canted rifle with plumb sights will be accurate- hit the ‘X’- at only one distance from the muzzle. Not an issue when shooting known distance targets.

      • BB, what is the effective range of sights like this? Same as with a scope or open sights or are they really more limited to 10m target shooting? I have tried a couple but have neither one fit me, cheapies that would not set far back enough so I just threw a scope on.

        • Bob,

          I have put 5 shots of a .22 long rifle into less than 3 tenths of an inch at 50 yards with peep sights. Buffalo hunters killed buffalo at ranges up top 500 yards with them. The range is limited to your eyes.


  3. Get why it would be better to sight the rifle with both eyes open. Unfortunately that no longer works for FM since the left-eye retinal detachment 4 1/2 years ago, and despite later cataract surgery in that eye. That was reinforced when sighting-in the .22 Maximus with the CenterPoint scope at 25 yards yesterday…succeeded in zeroing it in well enough, but sighting only thru the right eye. “It is what it is.” Not complaining – glad to be still shootin’!

      • Delayed reply, RR – thanks for the advice; will try it, nothing to lose. Wonder if wax paper would work? Could try and rig up something resembling a monocle, call it the Half Dead-Eye Model.

        • FM,

          If you are really serious you can find a pair of shooting glasses frames with the white monocle to put on the left side. Many pistol shooters use them. BB probably has at least one pair.

  4. BB

    People’s eyes can differ but for most folks does the 10 meter blinder or in your case the rubber cup affect sharpness of the front sight at 10 meters or even 25 yards? Or does it just help the rear peep do it’s thing, which is to bring both the front sight and target into clear focus? I ask this because with my astigmatism a peep dramatically helps me even on a pistol and a lens peep can sharpen a blurry red/green dot optic.


  5. So what I was thinking about is say you shoot at different distances out to 50 yards and in plinking or at target paper.

    What distance is going to show the poi (point of impact) greater to poa (point of aim) or in other words each other. In closer or out farther or say the middle of your shooting distance like 25 yards.

    • Gunfun1,

      If I understand your question correctly it depends on your ZERO.
      But let’s say your far ZERO is 50 yards then probably at airgun velocities the middle of your shooting distance (near 25n yards) because of the arc of your trajectory; CANT is going to affect that part the most.
      I was looking at my targets from my last visit to the 100 range with my .177 SIG ASP20 shooting the JSB heavy Knock Out Slugs 13.34 gr. and it was obvious that much beyond the far ZERO (70) the drop is the bigger factor by a big margin and it grows almost exponentially leaving most every other factor to include wind effect out of the equation..
      I went from 2 MOA to 5 MOA and it was almost all vertical that made the difference.

      I think folks need to CANT around the clock! To include shooting their rifle upside down to get a feel for the effects of CANT and trying to adjust the aiming system to eliminate the effects.


      • Shootski,

        I mostly “plink” when I am shooting. Not many of the airguns around here will accept scopes or bubble levels for that matter. I learn to hold the old gals comfortably. It becomes repeatable. Repeatability is the secret to dealing with cant. If you are out hunting or plinking and your range is less than 50 yards, worrying about cant is a waste of time and energy. Just learn your airgun and how it should “feel” when you are shooting it.

        Now when I am doing long range shooting with my HM1000X, I am shooting off a bench with a scope with a bubble level inside. Then I concern myself with cant. When I am trying to put 5 shots in one inch at 100 yards, it becomes necessary to concern myself with any variable, including cant.

        I guess if you are seriously into competition or shooting prairie dogs in the head at 150 yards, you might be concerned with it. Edlee has it right.

        • RidgeRunner,

          I don’t want to plug up your ears again but learning the shift between POA and POI due to CANT is important to at least understand. Much more important is to understand how the Delta in POI and POA is properly corrected with the Windage and Elevation adjustment knobs and the impact of the trajectory at different points along that arcing path to the intended target.
          Airguns are changing and much more so the attitude of what is doable with them. I for one am glad the bb gun = toy mentality is on the wane.
          Edlee is correct in everything he discussed but for folks new to taking off ‘… prairie dog heads at 150…’ with airguns; knowing it will save them hours and hours of frustration.


          • Shootski,

            Do go ahead and stop up my ears. It is indeed important, most especially for the newbies to fully understand cant and how to correct for it. It can indeed throw a shot way off and if you do not have an understanding for it, you will chase the problem forever.

            When I first started shooting airguns, I would hang a string with a nut or some weight in front of my target. That would give me true vertical with which I could align my scope reticle with. Then I would educate my body to what “felt right”. I had subconsciously taught myself about cant and its affect on long range shooting in my youth. It is just one of those things I just do not consciously think about anymore.

            The closer the range, the less the affect. When using open sights, 25 yards can be a long shot, most especially for these old, tired eyes. Also, you learn the feel. How to hold that old gal and make everything come together. Amaze everybody at the fun shoot by hitting that 3/8″ spinner at 25 yards repeatedly, shooting an air rifle older than anyone there with open sights while standing.

  6. I saw one of the new Challenger rifles with this sight system at the Midwest airgun show recently. A VERY impressive package! And I’ve fiddled with a few sights in my day, LOL.

    As with any match sight, the best way to control depth-of-field in given lighting conditions is an adjustable iris unit. Hopefully Crosman will make such available?

    • Mike,

      I tried the Gehman plus other eyepieces in this sight. One or two were the right size but the wrong tread count. So they will attach, but they stop when they start to cross thread. I don’t remember if it was the Gehman or not.


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