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My FX Crown Story

This is a guest blog from reader Vana2, whose real name is Hank. Today he tells us the story of his new-to-him FX Crown precharged pneumatic (PCP) air rifle.

If you’d like to write a guest post for this blog, please email me at blogger@pyramydair.com.

Take it away, Hank.

My FX Crown Story
by Hank Vana2

FX Crown Mk2
FX Crown MK2

This report covers:

  • Why a Guest Blog on the FX Crown?
  • My new Crown
  • Initial setup
  • Pellet selection
  • Getting into the power band
  • Initial balance
  • The factory tune
  • Where are we now
  • A more conventional target
  • Summary

Why a Guest Blog on the FX Crown?

I would like to tell you about the FX Crown MK2 that I have and how I came to have it. I was not looking for another airgun as I have a couple that cover the “general shooter, hunter, plinker, pester” category that I place the Crown in, but this one was begging to be rescued.

It seems that the original owner had watched YouTube videos of shooting pigeons at 150 yards and decided that having an FX PCP would make that easy. The Impact he wanted was not available so he bought a Crown MK2. When the Crown did not live up to expectations he was looking to be rid of it. After publicly voicing his frustrations and generally bad-mouthing the FX and all their products there was little interest in his airgun. In fact a couple of friends tried to warn me that the rifle was a lemon and that I should walk away from it.

I tried to explain to the owner that the issues he encountered were easy to fix but he was adamant: PCPs were just a bunch of high-priced hype and he was done with them. In the end I traded for a lightly used (and slightly misused) .22 caliber FX Crown MK2 with a 500 mm barrel and a nice walnut stock. He was very happy with the deal and so was I.

I’m not going to get into all of the configurations of the FX Crown or into a detailed review of this airgun as there is lots of information and professional reviews already available on the net.

What I would like to do is share the steps I took to restore this .22 caliber FX Crown MK2 to its normal working state. The images included are of my working targets (that were rescued from the trash bin); nothing was specifically prepared for this guest blog so you are seeing my “raw” data.

My new Crown

The advantage of the Crown is that the power adjustments are easily accessible; the disadvantage of the Crown is that adjustments are easily accessible — and people can’t leave well enough alone so they turn up everything to “Full Power”.

Before taking possession of the Crown I confirmed that it was holding air and there was no obvious damage to the rifle itself. Exceeding the manufacturer’s maximum recommended pressures is a sure way to damage the seals, so air leaks are an indicator that the rifle was abused. I had fired a dozen shots so I knew that in spite of sounding strange it was working. All looked in order and, in addition to the rifle, all the usual paperwork and stuff was included in the gun case.

After a hardware check and pulling a patch through the barrel a more detailed inspection showed that transfer port, hammer spring and regulator were set to MAXIMUM. The gun was very loud, inconsistent and shooting at a much lower velocity than would be expected for a 160 bar regulator setting.

Initial setup

The Crown has 3 externally adjustable settings – the hammer spring (HS) dial; the transfer port; the regulator (with an Allen key) and one internal adjustment, the hammer spring pre-tension which requires the stock to be removed.

FX Crown Mk2 power adjustments
The HIGH/MEDIUM/LOW transfer port dial is on the left and the (MIN/1/2/3/4/5/MAX/A/B/C/D/E) hammer spring dial is on the right.

I could hear and see that the Crown was way out of tune when I first shot it. To get to a starting point where I could actually start to move forward with a tune I reduced the regulator setting to 100 bar and checked the hammer spring wheel tension.

It turned out that the hammer spring wheel had been messed with — the pre-tension adjustment screw had been backed out to the point that only a couple of detents on the CAM wheel were effective. To correct that I used an Allen key to tighten the pre-tension adjustment screw and bring the CAM to the point where, when turning the wheel, each detent actually changed the tension on the hammer spring. The neutral setting on the CAM wheel is very low but it’s a starting point and later I would dial in the hammer spring pre-tension to give me a useful range of adjustment for my tuning.

Pellet selection

The next task was to decide what I was going to set the rifle up for and to select the pellet I wanted to shoot. In my humble opinion, the Crown, with a regular thumbhole stock and the 500 mm barrel, is ideal as an off-hand plinking rifle, which suited me fine.

With a fixed power airgun like a springer, single-stroke pneumatic or a factory set PCP (without ready access to the adjustments) you go through the routine of finding the “golden pellet(s)” that best suits the power and harmonics of the airgun.

With an adjustable PCP you can select a suitable pellet and (can usually) tune the airgun to shoot that pellet well.

I chose a pellet weight to suit the energy level I wanted to work with for the application in mind — in this case: a general shooter, hunter, plinker, and pester. I’m looking for 30-ish foot pounds in a quiet shooter with a good shot count. Considering the 500 mm barrel, the JSB 15.8-grain (both the Hades and the Exact Jumbo) pellets are a good match. With a 600 mm barrel I would have gone with the JSB Exact Jumbo Heavy 18.13-grain pellet and I might decide to go there anyway — the 500 mm Crown has plenty of power to tap into and I have a good supply of the 18.13 pellets.

Shop SIG Sauer Airguns

Getting into the power band

In .22 caliber PCPs that have the power, most barrels are designed to work well with a velocity in the 880-900 feet per second (fps) range so I want to adjust the regulator to give me a velocity that is about 50 fps over that at the MAX hammer spring setting. This would give me a range of settings to test at mid hammer spring settings.

If the hammer force and plenum (the area between the regulator and the valve) pressure are out of balance the airgun will perform poorly. In theory, the ideal setting on the power band is 3 to 5 percent below the flat part of the power curve with a sufficiently high pressure to achieve the desired velocity.

A brief explanation: the hammer force (weight and spring tension) has to overcome the pressure behind the valve to open it wide enough and long enough to allow a pulse of air to propel the pellet out of the barrel. Insufficient hammer force or excessive pressure will upset the balance – this was exactly what my Crown was suffering from.

[Editor’s note: Pay attention to what Hank is saying here. This is how you set up a PCP. You don’t look for the most power. You look for a happy balance of power, accuracy and shot count.]

Initial balance

Usually, re-tuning a PCP to a different pellet is a minor thing because you are nine-tenths of the way there with the factory tune. In this case, though, the settings were so far out of balance that I had to start over from scratch.

I had (deliberately) gone low by choosing 100-bar reg pressure and a neutral hammer spring setting so I could find the initial balance between the two.

I’m setting the Crown up so that the velocities for hammer spring settings in the middle of the adjustment range will be in the preferred 880-900 feet per second (fps) range. This gives me some latitude to look around and try different velocities.

I started by shooting over the chronograph, increasing the regulator pressure until the velocities stopped increasing (indicating that the hammer spring was set too weak) then I would increase the hammer spring pre-tension a bit and continue shooting and monitoring the velocities. Through incremental adjustments and testing I found a place where, with 115 bar on the reg setting and the MAX hammer spring setting gave me the 950 fps that I wanted to work with.

I then tested all the detents on the hammer spring adjustment wheel to confirm that, from MIN to MAX, each showed a change in velocity. All was fine, indicating I had a good initial balance.

The factory tune

Efforts up to now have been to bring the Crown into a known good state. Now it’s a matter of trying different hammer spring settings looking for good groups and then fine-tuning the regulator pressure to optimize pellet stability and air usage.

This is the stage where I might try different brands or weights of pellets to see if the airgun had a preference. Typically people will test several pellets in searching for the optimum match. I had decided to focus on the JSB 15.89 as I was confident that the tuning would go well. If not, there was always “Plan B” — the JSB 18.13 pellets. The Crown has a variable transfer port (LOW, MEDIUM, HIGH) so I shot a card at the HIGH (shown below) and MEDIUM settings as well.

I feel that inconsistencies in pellet/barrel performance and tune don’t show up clearly at close range and that shooting a long range introduces variables (the shooter being the main one LOL!) that negatively influence the testing. I do my PCP testing at 40 yards which I feel is far enough to show tuning issues without being too far so that inconsistencies in shooting overwhelm the details.

Getting into the actual tuning, I did a quick sight-in at the mid-hammer spring setting to get on paper and then shot a card using different hammer spring settings. In addition to the point of impact rising, I expected to see the group size go from open to tight to open again as the velocities go from too low to too high.

FX Crown Mk2 on paper
Here I’m testing from MIN to MAX across the hammer spring adjustment wheel. As expected 3 & 4 showed good pellet flight (I pulled that flier on 4) the groups for 5 & MAX look good but they are shooting too hot and showing some spiraling – they all landed together at 12:00 o’clock but changes in distance would change the point of impact.

Once I’ve identified the hammer spring settings that shoot well I shoot a number of targets to determine which is best. At this point I’m monitoring velocities, watching for pellet stability and overall consistency.

FX Crown Mk2 evaluate settings
Here I’m testing various settings more closely. The “H5” in my crib note means transfer port HIGH and hammer spring 5. And 946 f.p.s. is the velocity at those settings. I also tested some MEDIUM transfer port settings. I’m currently using H and C (902 fps) on this tune.

These targets are usually a mess… a bunch of aim-points and with holes peppered all over them. I’ll pick an aim-point and shoot enough pellets to decide if I want to continue testing that setting or abandon it to try something else.

When I find a setting or two that show promise I’ll shoot a series of more formal targets to determine the one I’m going to stick with.

Just a note, my Crown has the earlier hammer spring wheel with a double-lobed CAM. One side is numbered and the other has alpha characters. Being slightly offset, the two CAMs complement each other – the velocity of “A” is in-between that of “4” and “5”. A bit confusing until you get used to it, the hammer spring dial on the new Crowns are all numeric.

Once I’m happy with the tune I’ll optimize the air usage. Ideally the volume of high pressure air in the barrel is just enough to launch the pellet at the desired velocity. Besides reducing the shot count per fill, excessive air causes a loud report and can destabilize the pellet.

I do this adjustment mostly by ear though I monitor the adjustments with a chronograph. By making small reductions to the hammer spring pre-load and/or regulator pressure I can optimize the air usage. As the adjustments are made the sharpness of the muzzle blast will diminish with only a slight loss in velocity. A sudden drop in velocity means that I’ve reduced too much and need to add a bit back.

The best combination of HS and regulator pressure is what I call a “factory tune” level. The airgun is shooting well; it’s accurate, consistent and efficient in its air usage.

Most people stop here and call it done. Nothing wrong with that but there’s still some tweaking that can be done if desired.

Where are we now?

Now that I’m at a factory tune I’m treating my Crown just like a new airgun, breaking it in getting and used to it.

Stats for this tune (15.89 pellets) are: Average= 902; High= 907; Low= 891; Spread= 16; SD= 5.8; Energy= 28.7 foot pounds.

I’ve noticed that with the large, rounded forearm and a high scope that I have to be particularly aware about canting the rifle. Still, on average, I’m keeping my shots within 3/16ths of an inch of my aim point at 40 yards — and I’m happy with that.

FX Crown Mk2 delta
This is one of my (many) practice targets. I like to shoot a session (25 pellets at 40 yards) and measure the distance (the Delta) from my point of aim (POA) to the point of impact (POI). I use the session average as an indicator of how accurate I was.

Once my Crown is broken in I’ll likely check the barrel indexing, polish it with some JB Bore paste and tweak the tune to see how low I can get the extreme spread (ES) for a 25 shot string. These bench rifle tweaks aren’t necessary unless you are shooting in competition for money but they are fun to do – kinda like sorting pellets, if you get my drift.

Being a working airgun I’ll be adding a sling and refinishing the stock to suit my preferences.

A more conventional target

I usually don’t bench shoot a PCP at under 40 yards unless I’m sighting in at the optimum far zero range. With the talk about the Pyramyd Air’s 25 Yard Challenge I thought – what the heck — there was a card on the 25 yard butt so I shot a couple of targets just to see what I’d get.

I still happened to have it so I included the card for reference. The dimensions are for the center-to-center group size.

FX Crown Mk2  25 yards
Since people are used to seeing groups shot at 25 yards I thought I would include this target for reference.

To interpret the target… the near zero on the FX Crown is 21 yards. Since I was shooting groups and didn’t want to blow away my aim point I just held dead-on and didn’t bother to compensate for the pellet rise or the wind blowing from right to left.

Summary

All and all, I’m very pleased with my trade. It took all morning to set everything right but the FX Crown is now shooting well. Being light weight and nicely balanced it is fast becoming a favorite.

There are deals to be had. Hope that sharing my experience with my FX Crown is of interest.

Cheers!

Hank

47 thoughts on “My FX Crown Story”

  1. Hank,

    Great report! You really explained very well how deep a “rabbit hole” pcp’s are.
    I hear guys are the range talk about tuning the regulator and the tuning there hammer spring. My eye just glaze over. Now I know why. Thanks,

    -Yogi

  2. Hank,
    Nice shooting on a rifle you are just coming to terms with.
    On a hunch the JSB heavies will do better out to at least 70.
    Great report and congratulations on the DEAL!
    Oh, and my eyes didn’t glaze over on your excellent detailed report.
    I will reread tomorrow but need to get some sleep as I have a HITT workout scheduled for the morning.

    shootski

    PS: For Yogi: Open Your Mind…Open Your Mind…you could find blue skys over Mars; all it takes is some PreChargedAir, Lol!

  3. Hank,
    Thanks for the report. I learned quite a bit from it. Makes me want to get out my old Marauder and go through another tune with it.
    I think sticking with a proven pellet through the tune is a good way to go.

    I finally have three Lothar-Walther barrels for my Low Pressure Pellet Gun: 177, 22, and 25 caliber. Before too long I want to share the results of my tests.
    Don

  4. Thanks for a very good report.

    You put things I n a way many people that have pcp’s but are hesitant to tune them may now have the incentive to try their hand at it.

    Your rifle was so far out of whack this suggestion didn’t apply to your circumstances.

    But I would advise anyone thinking of adjusting their rifle to record all of the settings as a known starting point before turning any adjustments (hammer spring, regulator settings, and valve spring preload, and transfer port settings if the gun has those adjustments.)

    So if your tuning attempts go awry you have a known starting point to which you can reset.

    Ian.

    • Thanks Ian,

      Thought that but with everything else, forgot to mention it 🙂

      The FX Crown manual, page 7, has a chart specifically for noting the factory and new user settings. Not surprisingly it was blank.

      I keep all my notes, tunes and stats in a special binder that I can refer to when needed to check base lines and settings.

      Hank

  5. Hank
    I keep telling people in order to troubleshoot and repair something you must ‘Understand’ how it works in the first place. You can’t just try to remember what you were told and rely on your memory to recall something. You forget, especially with complicated items.
    Once you understand how something works you know it and really don’t have to try to remember much. Everything kind of falls into place in your mind.
    Educating yourself on a given subject is the key to success.
    Not everyone has the ability to to understand very technological items. Especially if you are not very mechanically inclined or analytical by nature. That’s why people pay someone else to do things.
    I think you have done an outstanding job of educating us on this topic in a way that is easy to, “Understand”. Thankyou, much appreciated.

  6. Very interesting. Your friends said this gun was a lemon, and you made lemonade! Nice work and nice shooting!

    Is it too much to ask of these guns to be accurate at different power levels? It seems to me that would be part of the reason for having external adjustments. I am imagining one could reach out for longer range hunting or pesting but then dial it back for pesting inside a barn or storage building.

    • RG,

      It would be “possible” to have one air rifle that would work well at long range and close range, most especially if you know the “settings”, but in practice you would likely have to go through all of this every time you “adjusted” it. The best scenario is to adjust it to where you want it and leave it alone. You get a different air rifle for different scenarios of shooting. You are talking about going from likely 100+ FPE down to 12- FPE. That is quite a power spread. You are not only going to be using different settings, but likely different pellets.

      • So it’s possible….

        Actually I understand your response, RidgeRunner. Perhaps the controls are not so precise that even if you knew the settings, you would still need to sight in to make sure where you would be hitting. So if I understand let’s say I had an FX Crown dialed in for 50 yards for popping woodchuck. And let’s say I had previously dialed in a different pellet for sparrows at 10 yards. I could not switch back and forth because I could not be sure the controls could bring me precisely back to the same settings without some fine tuning?

        • Nope. You would have to do a new “tune up” each time you changed it. Like BB said, your best bet would be one of the AirForce rifles. You already have an air rifle that would be suitable for in the barn shooting. You do not need or want much power there. What’s the problem. Just get a whacker and be done with it. You should have one dedicated for each use.

    • Roamin,

      If significantly different power capabilities are needed, you could look into the new crop of “hammerless” airguns like the Huben K1 and Leishy L2. I have a Huben in .22 and it does really well at this – there is nothing to “tune” with a hammer. and no conventional valve to optimize. It uses a firing valve that opens to flow air, and an adjustable closing valve that determines how much air is released. So the adjustments are the regulator pressure (externally adjustable) and a “power wheel” that controls the closing valve. While the gun is capable of upwards of 70 FPE for slugs, I have mine set to shoot only at around 30 FPE with pellets (it maxes at ~40 with Monsters as set) via a lower regulator setting, and I routinely dial it down to around 7 FPE for chipmunks that dig near my house (I don’t want high power pass through or misses when shooting at my house).

      While the POI is obviously very different like that, it is repeatable and can be learned. The power wheel has detent clicks and can be easily changed back and forth. I once even tested it loading the mag by alternating three different pellet weights and shot each pellet at it’s own wheel setting, changing on the fly – and I got three good groups and good chrony results for each pellet, despite the gun shooting differently on every shot. These are a very different kind of gun – complicated and expensive, but very likely the future of airguns. Worth looking into if after the “one gun” kind of solution – that said, I still have not got rid of any of my other guns, but it clearly is the one I shoot the most.

    • Roamin,

      On an airgun with indexed settings there is nothing stopping you from testing those settings to find one that shoots at less range and lower power than the one that the airgun was tuned to. It is a matter of finding the “golden pellet” for the power level that you are interested in that gives you acceptable accuracy at those reduced ranges.

      Many PCPs have hammer spring and transfer port dials so there are a lot of options to try.

      You can easily/repeatability dial back and forth between the settings for different applications. Lower power may not stabilize the pellet at long range but would probably be fine and give you minute-of-a-sparrow accuracy out to 20-25 yards.

      This dialing down the power should work within reason – if you tried to shoot a 13 grain pellet at 500 fps through a slug liner designed to stabilize a 30-40 grain slug at 1200 fps you would likely have problems 🙂

      Hank

      • Hank,

        “This dialing down the power should work within reason – if you tried to shoot a 13 grain pellet at 500 fps through a slug liner designed to stabilize a 30-40 grain slug at 1200 fps you would likely have problems ” That is the Golden Nugget I kept thinking about last night as I fell asleep and was going to share today.
        I have one other that is for bullet (SLUG) shooters: you have a wider band of adjustability for pellets because the don’t depend as much on spin stabilization than for bullets (SLUGS) which are totally dependent on spin rate for stabilization. For Bullets (SLUGS) you need to get the correct barrel velocity to get the needed spin rate for that bullet (SLUG) or higher which drastically limits your choices of projectile. Your only real option is to change the twist which means a barrel change if you want to really change your down range performance at the target.
        As B.B. has said many times, “You can’t change Physics!”

        can’t wait to hear how far you and the heavy pellets can get!

        shootski

      • Hank

        Thanks for the well written tutorial keeper for all PCP folks.

        BB’s “golden gun” (Ataman P16) is still performing. Readers may recall that based on BB’s tests for this pistol I was lucky to win, I turned the hammer spring tension down almost to minimum to quiet the gun. Using the AA 16 grain dome pellet BB found to be best I did rested accuracy tests at 25 yards getting just over a half inch 10 shot group with its open sights. Given the accuracy and noise level now being backyard friendly from 200 bar down to 120 bar, I ordered a hand pump and chronograph from PA. Scoped I sometimes get 10 shot groups in the .40’s at 25 yards. At first I wanted to stretch its legs at the rifle range but some readers warned I may not be able to find the sweet spot again if I changed the settings. I took that advice.

        Hank, you no doubt have a well thought out shooting setup. Shooting this many pellets for accuracy through a chrony without shooting it takes both skill and concentration.

        Deck

  7. Hank,

    Awesome! You have written out in easy-to-understand terms what I and others go through without conscious thought. There are quite a few “tips” in this report I could use to improve my tuning, such as better record keeping.

  8. I am reminded of a Forest Gump quote, “stupid is as stupid does”. Some people won’t listen to those trying to help them. I’m glad you recovered the FX Crown from the grave / closet. A very sweet looking and shooting rifle!

  9. Hank,
    This rifle is a beauty, and I’m glad to see that you got her perking properly. Thank you for the well-written report on how you got there. You were being modest with naming this report, but you could have titled it something like: “Tuning tips for the out-of-whack PCP” or something to that effect.
    I think it’s likely that B.B. will file this one away in his PCP tuning tutorial files. 🙂
    Cheers,
    dave

    • GF1,

      The guy decided to get into bow hunting deer.

      I traded him enough equipment – a compound bow, matching arrows and all kinds of accessories – that he’s completely setup.

      …That and some instruction on how to use the stuff 🙂

      Hank

      • Hank,

        “…That and some instruction on how to use the stuff”
        Hopefully just enough that the deer will have nothing to fear…I would rather he go after the Pigeons!
        From your limited references to him he sounds like a Squab eater!
        shootski

  10. BB
    A bit of Senior B Day humor. Had an internet chat with an old friend from Brooklyn I grew up with. He did not know I had a stroke and inquired about it.
    Told him all was fine and had no symptoms except that when I go for a walk now my left arm flies up and I turn left every 10 feet. I can only walk in squares. We were constantly throwing zingers at each other and he immediately replied, “Well look at it this way, if you ever get senile or come down with dementia you will never walk off and get lost ! ”

    Found out we both frequently fall asleep while in our recliners watching TV these days and in closing our conversation he warned me, “What ever you do, don’t recline your seat while driving your new car !”
    Good friends for life are priceless.

    • Bob M,
      Sorry I can’t help but think you mite be perfect for NASCAR.

      My friend has a blind dog that only makes left turns. It takes him a long time to wander off.
      Don

        • Bob M,

          But I was just toasting B.B.’s birthday!
          Then I got into the other sailor toasts and pretty soon i got to toasting the Queen!
          Circular Toasting…
          Well I’m “toast” going to see if I need to put my foot out to keep the room from spinning…
          G’night!

          Now I lay me down to sleep, my Viggen is parked across the street and if my hand brake slips I pray to God he will step on the brake. Amen!

          shootski

          • Shootski and ALL
            I have and will share with you a wonderful secret I discovered many years ago when I spent a great deal of my time camping and 4 wheeling in the desert in Southern CA.
            Most times we would each bring a case of beer for the weekend and often have to make a beer run before it was over.
            We partied from morning to night barbequing everything from ribs to chicken and ended every night sitting around a big campfire recalling our sea stories.

            One night I got real hungry after jumping into my tent for the night so I opened a can of ‘Chili Con Carne With Beans’ and ate it cold right out of the can. Not really cold, we were in the desert, and it was really good. To my surprise I started to sober up as I was eating it. The next morning there was absolutely no sign of a hangover. Needless to say I started eating a can of it after every day of drinking before going to sleep from then on.
            I finally found the way to prevent a hangover !
            Questioned my doctor about it one day and he said it was probably the best thing to eat because it provided more needed protein than anything else to return to normal.
            Pass it on !

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