Shooting Chrony Alpha Master

by Tom Gaylord
Writing as B.B. Pelletier

Alpha Master chronograph
Shooting Chrony Alpha Master chronograph has a control box with display that separates from the skyscreens by 18 feet. These chronographs are shown with their light diffusers attached, but I don’t use them. Read why in the report.

This report covers:

  • What about the false triggering of the skyscreen?
  • Start screen — stop screen
  • Atomic blast wave
  • The solution to false triggering
  • How I use the new chronograph
  • Battery operated
  • Light diffusers
  • Summary

As you may be aware, I shot my Shooting Chrony Alpha chronograph with the Benjamin Bulldog big bore air rifle. It wasn’t the rifle’s fault — it was mine. There were other shooters on the range, so I had to place the chronograph about 10 feet in front of my position to get the skyscreens out from under the metal roof that hangs over the firing line. For range safety rules, I could not get closer to the chronograph. So, I was pointing the airgun to shoot over the skyscreens.

Unfortunately, the Bulldog is a bullpup design that has a heavily shrouded barrel. It doesn’t point very well. On one shot, I pointed too low, and a .357 bullet hit the plastic skyscreen enclosure and the metal case.

Benjamin Bulldog chronograph
I hit the chronograph with a .357 bullet.

To its credit, the chronograph continued to function. Even with the shielding blown away, the skyscreen sensor wasn’t damaged and still sensed the passage of the bullet, but I was concerned how long it would last. I asked Pyramyd Air for a replacement chronograph, and this time I requested the Alpha Master, which has a control unit that separates from the skyscreens by 18 feet. That would allow me to shoot at the range in safety. In fact, I’ve been to the range 2 more times with the new chronograph, and it works exactly as planned.

What about the false triggering of the skyscreen?

I’ve touched on this topic several times over the past few weeks. My new chronograph has had some false starts. The first mention was when I tested the Diana 45 after the tune. I got some velocities that were hundreds of f.p.s. too slow in the middle of strings that otherwise seemed normal. If I’d never seen this sort of behavior before, I would have easily been tricked into thinking the gun was at fault. But back in 1994, when I wrote the R1 book, I had a similar experience that was due to the early triggering of the first skyscreen.

Start screen — stop screen

The skyscreens are photoelectric sensors that detect small changes in light. When a pellet passes over a screen, it casts a slight shadow and the sensor detects a slight drop in the light it’s receiving. That’s why lighting is so important to chronograph operation.

The first skyscreen tells the onboard computer to start counting the time, and screen 2 tells it to stop. Since the distance between the 2 screens remains fixed, it’s possible to count the time it takes the pellet to pass from the center of screen one to the center of screen two — and use that to calculate how fast the pellet’s moving. If the first screen — also called the start screen — is triggered early, the computer counts a longer time before the pellet crosses the stop screen, and the pellet’s velocity is calculated to be slower.

But how can an optical sensor “see” anything before a pellet passes over to cast its shadow on the screen? The answer is distorted air waves that get past the pellet as it leaves the muzzle. You’ve all probably seen something like this, but you didn’t know what you were seeing.

Atomic blast wave

When an atomic bomb detonates, a white ring of energy moves out from the blast at supersonic speed. It’s visible in the air and on the ground for several miles. This white energy ring is compressing the air it passes through at supersonic speed. The air the energy wave passes through condenses when it’s compressed, and that’s the white color you see.

When a pellet gun fires, the compressed air escapes around the pellet at the muzzle. While it’s similar to the energy wave from the atomic blast, it isn’t the same. In this case, it’s just the air that was compressed in the barrel behind the pellet. For a short distance, this compressed air appears as a visible distortion in the air. The first skyscreen can sense this distortion for a few inches from the muzzle, and that’s what sometimes triggers it to start the counter. Since the distorted air moves faster than the pellet, the start screen starts early.

I’ve tested my new Alpha Master for this phenomenon with other pellet guns, and I’ve found the skyscreens on the new instrument to be very sensitive — much more sensitive than the screens on my old Alpha chronograph. Sensitivity probably varies from sensor to sensor and is not specific to any certain model of chronograph. I’ve also seen the same phenomenon with my Oehler 35P chronograph, as well as with a very old Shooting Chrony I used to have.

The solution to false triggering

The solution is to keep the muzzle of the gun back from the start screen far enough to allow the distorted air to dissipate. Shooting Chrony recommends 3 feet in their manual, but I’ve found that 2 feet is far enough for my new chronograph. Firearms shooters rarely see this phenomenon because they usually shoot from at least 10 feet back. At that distance, even the much more pronounced shock wave of expanding gasses from the burning gunpowder dissipates. But I shoot in my office, where I used to hold the muzzle 12 inches from the start screen. I have to be farther back with my new chronograph.

How I use the new chronograph

I normally don’t need to separate the skyscreens from the control box when testing in my office. I have a table next to my desk with the chronograph permanently set up because I usually chronograph 100 to 200 shots each week. So, that 18-foot cable remains coiled up on my desk. All I do is position a 500-watt halogen light to shine on the white ceiling above the skyscreens, and everything works perfectly.

When I do go to the range, it’s a simple thing to uncoil the cable and set up the chronograph to work remotely. I can then set out the skyscreens on the range and operate the chronograph — including turning it on and off — from the safety of my shooting bench.

All of the mathematical functions of the Alpha model are present in the Alpha Master. I can record up to 32 shots in a string; delete any numbers that I don’t want in the string; and calculate the average, fastest shot, slowest shot and the standard deviation of the string. The power switch is on the remote unit, so I’m in complete control of the chronograph, even when it’s downrange, where I can’t go.

The Shooting Chrony registers velocities under 1,000 f.p.s. as decimal fractions, so I get numbers like 732.4 f.p.s. I don’t report these decimals in my blog articles. I round them up or down in the conventional way (0.5 to 0.9 is rounded up to the next higher whole number and 0.1 to 0.4 is rounded down to the lower whole number).

Battery operated

All Shooting Chronys run on one 9-volt battery, and they last a reasonably long time. You’ll get a low-battery indication before the instrument dies. So, pay attention to the display, and you’ll never be without a chronograph.

Light diffusers

Every Shooting Chrony comes with 2 white plastic light diffusers to let the skyscreens “look” at even lighting. You see them on their posts in the first picture. I never use them. They’re for those days when there are fast-moving clouds in a bright blue sky or for when you’re in direct overhead sunlight or under overhead cover that casts uneven shadows. Indoors, I point my skyscreens at a white ceiling, and outdoors I use either the bright blue sky or an overcast day. Overcast days are ideal for skyscreens.

Summary

When it comes to chronographs, shooters never had it as good as we do today! When I was young and personal chronographs were new, they didn’t have skyscreens. They had paper screens with wires embedded in them. The instrument registered the breaking of the wires as small changes in conductivity, so you only got a few shots at a screen before it had to be replaced. Buying replacement chronograph screens was a considerable investment for a shooter.

The chronographs of that time didn’t read out in numbers, either. They had lights arranged in columns — sort of like the computers from a 1950s Buck Roger’s movie. When you fired, some of the lights illuminated, and you had to look up what they meant in a table. You didn’t get an exact velocity. You got a range of velocities, like 2,140-2,148 f.p.s.

You paid $300 and more in 1960 dollars for these instruments and counted yourself fortunate to be able to own one. Just a decade earlier a chronograph cost about $100,000 and took a trained person to operate! See Smith’s Standard Encyclopedia of Gas, Air and Spring Guns of the World for that one!

So, shelling out $100 and change in 2015 is peanuts for what you get. I was amazed to discover the difference between the Alpha model I had and the new Alpha Master model I got is just $7.04. I would pay a lot more to get the ability to control the skyscreens remotely.

59 thoughts on “Shooting Chrony Alpha Master

  1. Fluorescent lights flicker on and off, and will cause random, false triggering, unlike incandescent or halogen lights. If you have those indoors, you have to turn them off and use incandescent, halogen, or LED lamps that are not dimmed with pulse wave modulation circuits, or at least swamp them out with a very bright incandescent or halogen light, like BB does. I added LED strip lights to the underside of the sky screens for indoor use.


  2. One of these days I am going to have to break down and get me one. I have not really needed one that much up until now, but with me doing a total rebuild on my Talon SS, it would be a most useful tool.

    There is a danger of obsessing over the numbers, but that is what some people are really into, so I guess that is OK also.


  3. I wish I had gotten a model with the remote readout for the convenience. I ended up getting the printer to go with my F1 Shooting Chrony which works well. I set mine up in my garage about ten feet from the muzzle directly in front of my rubber mulch / 5 gallon pail pellet trap. After having issues with failures to read with LED pucks and other lights I just went ahead and got the factory infrared LED light set. Since then I have never had another misread, not one. They are well worth the money for me, but I only use them inside, so I haven’t tried a mobile battery setup.


  4. I’ve got a Beta Master and love it. It’s been very reliable. The Master series, with the remote display, is a major convenience, allowing you to set the display wherever you want. I got the Beta for its ability to download data to a computer but have yet to actually spring for the software and cable that let you do it; been inputting the numbers manually, old-school style.

    The Chrony has been most valuable in letting me know how my guns are actually performing, and the number of good shots per fill to expect on my CO2 guns (Was that just a flier or is the velocity borderlining?).


  5. A warning to all men that buy a Shooting Chrony Alpha Master that are married to someone other than Edith:

    I purchased a Shooting Chrony Alpha Master, and have zero complaints. However, after using it one day, I could not get the cord to fit in the box with the chrony from whence it came. So I wrapped the cord and put it on the top of a desk in the spare bedroom for the time being.

    Mrs. Slinging Lead, as helpful as she is, decided to tidy up my desk and stow the cord in a place that happened to be a drawer from a discarded desk in a cluttered garage, which she did not remember, but I have been told is my fault. After a frantic fortnight of searching, and foregoing what was left of my sanity, I finally found it.

    Long story short, this Chrony is useless without the cord, which is not an item you can buy at Radio Shack. So keep the cord close at hand, especially if someone helpful like Mrs. Slinging Lead lurks about.

    Also, I would say that BB’s new and improved chrony is just as susceptible as his old one to the odd stray pellet. His couch and walls could testify to that, if only they could speak. So aim carefully.

    Now you’ll have to excuse me while I search for the spackle. I have a hole in the ceiling I need to patch.


    • Buldawg got a shorter cord for his through Walmart.com. I’ve considered following suit,the original18’er is a bit long for my needs and becomes a problem in transport so a shorter one would come in handy most often but 18′ will put you farther away than may be safe for it’s own good,especially on high powered scoped guns
      I tagged mine the first time about a month ago and was really glad I sprung for the mobile readout because that’s exactly where my 2400 put one of the ” heavier than average” .22 pellets I was [email protected]+ fps.


    • Yes, I noticed with all my gun equipment that I have had to do frantic searches for tiny parts that are absolutely essential. The last one was finding the cleaning kit for my Saiga so that I could use a slot cut in the end of the container as a lever in part of the disassembly of the rifle. Thankfully I had kept the original box.

      Chronographs seem like a black hole of technical problems. With everything that could go wrong, it seems like you would always be wondering if your data was really correct. Definitely, a labor of love.

      Matt61


    • Slinging lead
      You can by new different length cord from wally world online or from tiger direct which is where wally world sources them. it is an RJ-12 male to RJ-12 male modular straight cable 6 wire single plug cable and the part number for a 7ft cable on the package is #09598.

      I am not sure if that is the number that wally world uses but it was only around 8 bucks with shipping if I remember right

      Just search wally world or tiger Direct for RJ-12 male to male cables with 6 wires and you should find a length you like as chose 7 foot which allows me to place the chrony 3 feet from the muzzle and still have the remote next to me. They make them in multiple of 7 feet lengths and the 24 foot cable that came with mine I found to be impossible to get back from where it came out of but the 7 foot coils right up and fits inside the rear half of the case and folds up very nicely .

      I found a camera tripod in new condition at a garage sale for 3 bucks so mine stays mount all the time but the cord in coiled up at put in the rear half so the better half cannot clean up and hide it from you. LOL

      BD


      • Bulldawg

        I very much appreciate your reply. I did eventually find my chrony cord, so I am not in need of one at this time. However should I find myself in that position again, the information you provided will be most helpful.

        At the time I lost my chrony cable, I actually found a cable that would allegedly work, but it didn’t. It had the right number of contacts, it fit in the chrony cord sockets, but alas no dice.

        Perhaps the cord was bad. Using the information you have provided, I am confident I can find a replacement, should the need arise.

        Thank you for kindly providing this valuable info.


        • While RJ-11 connectors run to 6 contacts, many of the ribbon cables used with them only populate the center four contact points (two contacts per phone line — supporting a two-line phone).


        • SL
          I did notes my cord that came with my chrony but found it to way overkill and far to long for my needs so that is why I found and ordered the shorter cable.

          it is good to know that it is just a plain 6 wire phone cord so it is no problem to replace or get a different length if so desired.

          Glad I could be of help if you ever need to purchase a new one.

          BD


          • I’d have to check the existing cable for full details first. I’d only commented that the RJ-11 connector has provision for six contacts but most phone cords only populate four of them.

            But there is still the potential that the Chrony remote cable plays tricks.

            Phone patch cords are commonly wired straight through (especially these days when phone line polarity is ignored by the phone). That is, if you aim the RJ-11 connectors at each other, with the contacts up, you’ll see that the colors of the wires will carry through. (I don’t have the color scheme memorized)

            B-><-Y

            Or, if you number the pins from left to right

            | | | | (just a common 4 connector phone patch)
            1234
            BRGY the other end will be
            4321
            | | | |

            The cable for the Chrony IS 6-pin, BUT has a 180-switch from end to end. Trying different ASCII art… Side view phone patch

            ——=================——
            \ /

            —- contact
            == cable
            \ and / are the lock tabs

            Side view Chrony

            \
            ——-================——-
            \

            Easy to make IF you have a supply of 6-lead flat cable, a pair of RJ-11 6p6c connectors, and a crimp tool.


            • Forgot to guard the > and < signs, so the forum ate some of my post. And you have to visualize some of the \, / markers slid to the right end of the “cable”.


            • BW
              The RJ -12 6p6c male to RJ-12 6p6c male cable I referenced in the above post to SL is what I have for mine in 7 foot length and it works just fine so I think you arte trying to over think it and making it harder to get the correct cable than it is as my package that my 7 foot cable came in had the exact info I gave DS above on the package

              BD.


              • Should you get a chance, lay that 7ft cable out flat and see if the connectors are in the same orientation at both ends (that is, if you start with copper pins down and the lock tab on top at one end, and slide your finger along the length, is the lock tab on top at the other end?).

                Most normal phone cords are made with the tabs on the same side. The Chrony cable isn’t.

                Normal phone wiring is to put line-1 on the innermost pair, and line-2 is the next pair out (and the outermost pair aren’t used). Since modern phones ignore polarity, it doesn’t matter if one end of the cable is “reversed” compared to the other end.

                The Chrony, however, is supplying DC power over that cable, and having common phone (lock tabs on same side, straight-through) would end up reversing the + and – power leads when compared to a cable that reverses the connector at the far end.


                • BW
                  I did as you said and slid my hand along the flat cable and the connectors are opposite at each end IE. The lock tab is up on one end and down on the other. I have used this cable 100 times with no issues with the chrony at all so it is wired right but it is an RJ-12 6P6C cable not an RJ-11 cable.

                  So all I can say is that if you get a RJ-6P6C cable in whatever length you choose it will work it just cannot be the standard RJ-11 cable that has 6 places in the connector for wires but only four wires filling those slot it has to be an RJ-12 6P6C cable.

                  BD


                  • Based on Wikipedia, the whole realm of RJ connectors is a mess (RJ-11 is supposed to only be a 2 conductor version).

                    Also, based on Wikipedia, the proper cabling requires the connector to be flipped at one end, so that a wire is at the same connector position at each end. I suspect many of the “RJ-11” (with 4 wires) that I have are technically incorrect, as they have the connectors face up on both ends, meaning the line pairs swap polarity going from one end to the other.


                    • BW
                      I may have just got lucky but I have a 14 foot cable and the 7 foot cable both from wally world online and they both work as well as the 24 foot cable that casme with it that is entirely way to long for air gun use.

                      I could see it for firearms as the muzzle blast from some rifles can be 10 feet out from the muzzle but I only use it for air guns as firearms I do not reload so I shoot what I buy and it is of no concern for the fps as long as it hits what I aim at.

                      BD


  6. I bought the cheapest green chrony (too lazy to go to the garage and look at the box). The first shot that I ever attempted to fire over it hit the second sensor, and cracked the housing. Since then, I’ve used it for 1000’s of shots to tune anything from 2240 based builds, to my Drozd Blackbird, and even slingshots. Anybody who is a regular here should own one!


  7. They are well worth having. I bought the Bata Model a few years ago. It can be an eye opener. I was surprised to find that one of my .25-06 handloads was doing 3320 fps. with no pressure issues.

    Mike


    • They are going very versatile tools we chonyed glossary guns with mine and if I ever get used to it enough I’ll be clocking my rebuilt wristrocket but I’m missing something to weigh projectiles with. Guess I shouldn’t have sold that triplebe and weight set!


  8. A little while ago I read a reprinted American Rifeman article from 1940 on how to build an inexpensive chronograph using commonly available parts (for the time). If you’re interested the link is below if you know where to get a Ford Model T coil it could be fun to try.

    Link: http://www.americanrifleman.org/articles/2015/1/7/throwback-thursday-a-simple-chronograph/

    BB – I’m new to shooting and air guns and you are providing me with a great eduction, thank you.


  9. B.B.,

    I have the Shooting Chrony Beta Chronograph. I thought it would be more useful than it really is to be able to permanently store the data. On second thought I would rather have the printer but that is another $108.

    Chrony’s are not only useful for improving your shooting experience but they are also just plain fun to play with. I got mine based on your recommendations and the things you use it for. Thank you for that.

    G&G


  10. I mostly use my Chrony for outdoor centerfire load testing. Long ago, I concluded that lighting conditions can make for occasional erroneous readings (either slightly high or low). As the bullet passes over the two “skyscreens,” I think the skyscreen sensors can “trip” when the bullet is in a slightly different position over one screen than the other. My experiences are different from B.B.’s. If it’s sunny outside, I must use the diffusers to reduce the likelihood of these erroneous readings.


  11. B.B., thanks for the invitation to the Texas gun show although I will have to regretfully pass it up. My traveling is overloaded as it is. I’m satisfied with my spring guns now which don’t have perceptible vibration. But perhaps your guns would be smoother than smooth and introduce me to some dimension that I was not aware of.

    Mike, confidence! I may be within 1/5 gr. of licking the problem with my M1. My next range trip could be critical. What kind of groups do you get with your M1 with the National Match modifications? The reason for my troublesome gas adjustment system is that my gunsmith said that you really need it to reliably go under one MOA with the M1. Otherwise, the piston action will throw off the accuracy. If worse comes to worse, I can just send the gun to a gunsmith and get him to crank the system all the way open which will return the gas port to the original size and effectively dismantle the system. But I’m not ready for that yet. That makes sense that 4064 is in the allowable range of powders for this rifle. My gunsmith said that it is fairly common among match shooters.

    Speaking of gas systems, do you know the purpose of the gas tube on the AK that gets removed as the last step in field stripping? My guess is that this is what channels the gases from the discharge to drive the piston that operates the gun. But I was surprised to see that the face of the gas piston is much smaller than the diameter of the tube. This seems much different from the M1 where the diameter of the gas tube is much smaller. Having such a large tube for the AK seems less efficient, but maybe it contributes to reliability.

    Is there a need to clean this tube regularly? The gas system of the M1 in contrast is supposed to be almost self-cleaning and needs little attention. If I’m understanding the gas tube of the AK, it should be filled with powder residue after shooting. On the other hand, the accumulation wouldn’t affect the action of the gun for a considerable time. So, I’m guessing that the answer is no.

    Matt61


    • That tube contains the gas that is bled from the barrel to operate the action. It is self cleaning for the most part but if you are shooting corrosive ammo, it is a very good idea to clean it. There is enough clearance to allow for dirt and fouling. It still works when dirty and even rusted.

      Mike


    • With my M-1, the very best group I have had was 1/2 inch @ 100 yds. But, more often it runs around 1 1/2 inch with my handload. Not bad for a GI barrel. When I received the rifle the barrel was new.

      Mike


  12. Got my pump in today and now the fun part;pumping and looking for leaks at the same time is a job for more than just me. I was supposed to have a helper coming over when it arrived but somebody’s windshield wipers went out this morning so instead of going to work he drained a 12pack of Busch.
    Gotta go to court @8:00 tomorrow,then Physical therapy after lunch so it’ll be a few days I’m sure.


    • Pulled out the extension and went through the break-in for the HIpac and got over10 shots outta1000psi.I’m sure they’re flying faster than co2 but I’ll have to chony it on a warm sunny day to get the light right.


      • Had to try the extension again after a visual inspection and now I can’t get any pressure again even after pulling it back out.I got a rebuild kit with it but gotta find the leak beforeI can fix it.



          • 2400KT, I installed the Hopscotch last night and got the pump today,including the extension but couldn’t build pressure until I pulled the extension back out then went through the break- in for it’s check valve , pumped up to 1000 psi which got me 10 good shots,drained it to replace the extension and now I’m wondering if it could be the original face seal but can’t get the Hipac back out to inspect without complete disassembly.
            That ain’t happening tonight!



            • Reb
              I was afraid you may have issues with that hipac and it could be either the foster pin o ring not sealing or the seal in the end of the valve has blown out from under the hipac nipple end .An o ring on the extension or other threaded ends would not leak that fast without you seeing it squeezed out between the tube sections. I would take it all apart and inspect the foster fitting pin o ring as mine got cut every three to four fills as the machining where that o ring sit on mine was very rough with sharp edges that cut the o ring easily also the seal in the front of the valve could have blown out from under the nipple end of the hipac end that threads into the gun.

              If you cannot get any pressure to build then it is a seal or o ring that is cut or blown out of it pocket which requires complete disassembly to find and fix.

              Good luck and let me know if I can help.

              BD.


              • I’be had those extension seals squeeze out on me a few times, so I keep plenty around. I’be never had the foster O-ring issue though…that sounds like a major problem! I still use the Crosman face seal on all three of my guns without any issues, although I never fill past 2250psi.


                • DS
                  I had nothing but issue with mine with o tings squeezing out, foster pin o ring being cut after 4 to 5 fills of 2200 psi and the seal in the pocket of the valve being blown out.

                  When assembled my hipac with two extension looked like a banana as it was bowed very badly and when installed with barrel bands it would try to straighten it out and spread open the extension joints allowing the o rings to squeeze out and also the foster pin o ring surface inside the front tube was rougher than 120 grit sand paper.

                  I finally trashed mine and got some disco tubes to replace the very poorly made hipacs after trying to explain the issues to a very uncaring and unknowledgeable seller as he would not stand behind his product or even admit that they are very poorly designed and much less even more poorly made with no quality control whatsoever.

                  it was 210 buck I just threw in the trash and will never give one red cent again.

                  I now have a 16 inch and 14 inch one piece disco aluminum tubed setup for my two 2240s that are straight and have no leaks or any issue and are far better looking and were half the price to boot.

                  BD


                  • I hope to do the same conversion on my .25cal 2400kt someday, but I haven’t carved out the time to research it yet. I’m sure it works way better, and is much more tidy looking to boot. I put my .25 cal kit together, but I think the hammer is binding in the tube, because I got 45 shots before I stopped counting on a single fill. All were passing over the chrony at around 450fps with little variation in velocity (with a 27.8 grain pellet). I should only be getting around 20-24 shots if it where tuned correctly.


                    • Ds
                      Yea that 25 should have ate way more air than that unless the hammer spring is way to light as I don’t think the hammer could be binding and it still shoot 45 times and the fps is way low even for 25 cal heavy pellets.

                      Do you have a hammer spring adjuster or are you just using the stock spring as with the stock spring and those 25 pellets it may give you 45 shots on a fill as a heavy pellets actually helps conserve air by pushing back against the air pressure being released by the valve and stall the air flow to some extent.

                      If you really want to wake up the 25 check out the jdsairman.com as he sells HPA adapters that allow you to use a big bottle on the gun that has a built in regulator that can be set to what ever output pressure you choose up to 1100 psi per shot and you will find the true potential of that 25 with one of his setups.

                      BD


                  • BD thanks for the tip…I’ll check it out. I’m using the same hammer spring/power adjuster that were on the same gun when it was .22cal (making 21fpe). I drenched the hammer and the spring in moly, so I think the viscosity might be bogging it down…


                    • DS
                      If you got moly grease all over the hammer and spring it will definitely bog the hammer down. I use just a light coat of silicone oil on my hammers and nothing on the spring but just a light coat of silicone were it ride on the spring guide and in side the hammer.

                      You may even need to go to a heavier hammer spring or add some weight inside the hammer in front of the spring to give some more inertia when hitting the valve or use a lighter valve spring or maybe even a combo of all three it all depends on what you are after. If you want shot count and less power then use lighter hammer and spring with stronger valve spring. If you want more power then use heavier hammer and stronger hammer spring with lighter valve spring.

                      it all having the right combo for the tune you are wanting.

                      BD


  13. Why do chronies need sky screens at all ?
    The ones at the paint ball field don’t have any, and appear to use a radar dish or something that is directional. There are even hand held versions that are about the size of a cordless phone that sell for $100-200, so the technology must not be too exotic 🙂


  14. B.B.,

    When indoors, I use a pair of Larry 8 LED pocket flashlights, one per screen. Turn the flashlight on and set it on top of the screen with the LEDs facing down. I use a Competition Electronics ProChrono Digital with the optional USB Interface for connection to my laptop. The flashlights are about $10 apiece.

    Jim


  15. If the chrony is reliable and the average fps is ‘acceptable’ to your needs, what about the ES?
    I’ve updated my ChairGun and found out a ‘new’ function = Vertical Stringing (last one at the ‘tools’).
    At least to my accuracy needs, very useful to be able to relax..

    Btw, B.B., what about that (deeper) ZR mount review?

    Marcos


  16. My fix for not hitting the aft sensor: put a brick or piece of wood laying in front of it. I grazed mine with a .22 pellet that took some of the top plastic off, repaired it with black electrical tape- working ok. I also use black electrical tape to mark the 4 inch height over the sensors on the screen poles.


    • I was gonna cot a plexiglass shield for mine,1/4″ thick and 1″ taller than the face should do quite well but it became a no issue while using it only at close range.
      Guess I really should mark the high and low permissable heights but I seem to have decent luck when I keep the shots under 3″ from the top of the face,which is very risky when testing shotcount


  17. I found out that when I first set up my crony. That rubber bands shot from the finger reach 150 fps and slows down to 123 fps after getting stretched out. So you can test a variety of thing as to how fast they go. This was for the funny side of a crony


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