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[ARCHIVED THREAD] - Chronograph accuracy (Page 1 of 2)
Posted: 10/14/2012 4:16:28 PM EDT
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How many of you guys have seen a significant difference in readings from one chronograph to another?
Have any of you guys compared your chronograph to another? |
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I would suspect that most reloaders are interested in relative, not absolute velocities.
Precision is more important than accuracy, I think, for our purposes. To answer your question, no I have never compared two chronographs with the same load at the same time. It would be best to fire shots through them alternately, and at least ten through each one. It would be an interesting, if meaningless experiment, because you have no way of knowing which one is "correct" as you have no way to resolve the ambiguity. |
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The old adage, "A man with one watch always knows what time it is. A man with two watches never knows what time it is" applies here. If you have two, which one would you trust? Unless you have access to a NIST time reference, trust the one you own. The Cadillac of chronographs, the Oehler 35P, lists a 0.5% accuracy. The 35P measures each shot twice (3 sensors) to reduce the chance of bad readings. Shooting Chrony also lists a 0.5% accuracy. CED and RCBS don't list an accuracy spec in their publications. Any of these will be accurate enough. At 3000 fps, a 0.5% error equates to 15 fps, while at 1000 fps, that is only a 5 fps error. |
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This has been a sore point for me over the last few months. The truth is you need to know both the relative and absolute velocities of your rounds. Relative because you need to know the MV spread so that you know you are reloading precise (i.e. reproducible) ammunition, and you need to know absolute velocity because that is what you use to get the correct dope when you shoot long range. I was using a Alpha Master Chrony which I just send in to get adjusted. In the mean time I brought a used Oehler 35P from a buddy of mine which I will line up with the Alpha when I get it. Will be interesting to see what the MVs are. |
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This has been a sore point for me over the last few months.
The truth is you need to know both the relative and absolute velocities of your rounds. Relative because you need to know the MV spread so that you know you are reloading precise (i.e. reproducible) ammunion, and you need to know absolute velocity because that is what you use to get the correct dope when you shoot long range. I was using a Alpha Master Chrony which I just send in to get adjusted. In the mean time I brought a used Oehler 35P from a buddy of mine which I will line up with the Alpha when I get it. Will be interesting to see what the MVs are. No, you need to shoot at those ranges and find out what your drop is. 
I had dope cards many years before I ever ought a chrono. |
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i once had my pro chrono and a Chrony brand set up next to each other at a match. I invited shooterst o shoot through them as to check their loads, and to satisfy my curiousity on how much they would vary.
I was amazed that in most instances they varied at the most 20 fps. Well within the what i would say is reloading tolerances. |
| I have shot the same round through 3 different units with the same shot. Chrony Beta Master, Pact, and CED were lined up at 10 feet from the muzzle and tested with five rounds from three different rifles. No significant differences were noted, with some shots within a few feet/sec. I meticulously recorded all this on my laptop in a spreadsheet and compiled this and other data in a file. Sadly the mess was lost a few weeks later when my PC hard drive decided to shit the bed. We did retest using just two units, as the Ohler owner was a no show. Bottom line, use them for approximate info for load development and dope cards that are proven at the range. The info is 'close' enough to be useful and often pretty accurate. Light and atmospheric conditions and alignment through the screens from shot to shot are important especially in cheaper units like the Chrony. |
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I would suspect that most reloaders are interested in relative, not absolute velocities. Precision is more important than accuracy, I think, for our purposes. I would like to work out a calibration routine for mine. To date, the best I have is to shoot 22LR ammo thru it (but it's too slow). To answer your question, no I have never compared two chronographs with the same load at the same time. It would be best to fire shots through them alternately, and at least ten through each one. It would be an interesting, if meaningless experiment, because you have no way of knowing which one is "correct" as you have no way to resolve the ambiguity. I don't agree with this philosophy, at all. I have had nothing but shit fits over the years trying to get the chronograph to display the same readings from the same ammo on more than one day. Heck, I can't even get it to repeat later in the same day. This problem is where accuracy and repeatability are important. The other issue comes out in the form of a question - if absolute accuracy is not important, on what time scale is it okay to have the chronograph drift/change calibration? How about over the space of 60 minutes (beginning and end of a testing session)? Furthermore, people are using chrono readings as part of their "pressure management" regimen. They won't go too high in measured velocity because they don't want to exceed safe pressures. Oehler used two chronographs to ensure they were both working correctly. I think that's a good approach. I'd like to have two chronos so I could have more confidence in either. You stack them in series and shoot rounds thru both, simultaneously. |
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Yes, I have seen significant differences between chronographs.
In a calibration lab, it is easy to find. In the field, you may or may not know it. The Oehler will at least flag the data if there is a significant difference between the two sets of signals. It also tends to be the best when all things are equal as in the calibration lab. |
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Chronographs are like women. When one starts lying nothing she says will make sense or add up. Same for me with chronograph. My main use for chronograph is used in conjunction with ballistic calculator and Kestrel. Once I get my one hundred yard zero and start dialing my scope in I'm gonna know if that chronograph is feeding me a line of shit or not. I've always gone on the cheap where chronographs are concerned, admittedly an Oehler would be nice but I've got holes in my rifle optics where money would be put to better use than a model Oehler 35P complete system at $575.00. A cheap hundred dollar chronograph will have to do for now.
eta, this where accurate records pay off from each day on range with Kestrel readings recorded. |
| I have two F1 Chronographs. Unfortunately, I have two because I shot one, not square on, but somehow hit the post in such a way that it dislodged and bent in the area near the sensor, and while it seemed to still be right, I wanted another one. I have shot ammunition through both of them within minutes of each other, but not over both of them at the same time. They are within a few fps of each other on average with the same load and conditions. All I can do is say that I also shoot a factory load that matches very closely to the advertised velocity for my rifle ( or one of my rifles ) to be sure that it is very close in fps to what my hand loads are. |
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Plasteredtex – yes I plan to line to two up and shoot though both at the same time. That way I should get three readings – two from the Oehler and one from my Master Chrony. Him – yes, you are right, one could never get an absolute velocity but the question is are you 50 fps off or 5? I could live with 5 but not 50. CharlieHo – yes I do in fact calculate/estimate velocity using my drop at 600 but with that method, you always wonder how much is actually due to your velocity or your BC. Best if you got more than one way to verify. In the end, at least for me, its not the actual velocity that I am most concerned about because as others have said, you can adjust/estimate using actual bullet drop. What burns me the most is when I get significant variations in MV from a batch of rounds that I am trying to get consistent neck tension and MV. When that happens I want to know that the variation is real i.e. I need to work more on my reloading and not just an error on the part of the chrony. That type of machine error can cause you to chase your tail and make reloading diagnosis impossible.
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I'd like to have two chronos so I could have more confidence in either. You stack them in series and shoot rounds thru both, simultaneously. Great plan, but we are back to the question of resolving the ambiguity if they differ. How do you propose to do that? |
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I'd like to have two chronos so I could have more confidence in either. You stack them in series and shoot rounds thru both, simultaneously. Great plan, but we are back to the question of resolving the ambiguity if they differ. How do you propose to do that? You are assumming they will differ. I have used the Oehlers chronos successfully many times. Both channels were in amazingly good agreement with each other and with expected values. The trouble comes from other, less expensive units and thier lack of calibration and lack of consistency. The troubles I've had with my PACT are so bad I basically do not trust it for much of anything, anymore. I now have a CED, as well. Some day, I will get them both onto the range at the same time. I hope to find the trouble derives from the (crappy, flimsy) skyscreen designs used by all these inexpensive chronographs. If it is that, I can remedy the problem. If it is inherent in the electronics (drift due to temperature sensitivity, calibration offsets due to bad capacitors or ,...), that is in a different league, altogether. To me, it is key to not just give up. The key is to identify the problems and limitations and get them remedied. This is, in part, why I believe chronograpjhs are not necessary for reloaders - they are not reliable or accurate. Until I resolve these instrument issues, I rely on my zeroes, not on my chronograph data. |
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Quoted: +1 Exactly!Quoted: Quoted: I'd like to have two chronos so I could have more confidence in either. You stack them in series and shoot rounds thru both, simultaneously. Great plan, but we are back to the question of resolving the ambiguity if they differ. How do you propose to do that? You are assumming they will differ. I have used the Oehlers chronos successfully many times. Both channels were in amazingly good agreement with each other and with expected values. The trouble comes from other, less expensive units and thier lack of calibration and lack of consistency. The troubles I've had with my PACT are so bad I basically do not trust it for much of anything, anymore. I now have a CED, as well. Some day, I will get them both onto the range at the same time. I hope to find the trouble derives from the (crappy, flimsy) skyscreen designs used by all these inexpensive chronographs. If it is that, I can remedy the problem. If it is inherent in the electronics (drift due to temperature sensitivity, calibration offsets due to bad capacitors or ,...), that is in a different league, altogether. To me, it is key to not just give up. The key is to identify the problems and limitations and get them remedied. |
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I'd like to have two chronos so I could have more confidence in either. You stack them in series and shoot rounds thru both, simultaneously. Great plan, but we are back to the question of resolving the ambiguity if they differ. How do you propose to do that? You are assumming they will differ. I have used the Oehlers chronos successfully many times. Both channels were in amazingly good agreement with each other and with expected values. The trouble comes from other, less expensive units and thier lack of calibration and lack of consistency. The troubles I've had with my PACT are so bad I basically do not trust it for much of anything, anymore. I now have a CED, as well. Some day, I will get them both onto the range at the same time. I hope to find the trouble derives from the (crappy, flimsy) skyscreen designs used by all these inexpensive chronographs. If it is that, I can remedy the problem. If it is inherent in the electronics (drift due to temperature sensitivity, calibration offsets due to bad capacitors or ,...), that is in a different league, altogether. To me, it is key to not just give up. The key is to identify the problems and limitations and get them remedied. This is, in part, why I believe chronograpjhs are not necessary for reloaders - they are not reliable or accurate. Until I resolve these instrument issues, I rely on my zeroes, not on my chronograph data. The word "if" is not presumptive, it is conditional. You are evading the question. You chronograph one shot. The readings are 2730 and 2796 and the two instruments continue to differ by approximately that amount on subsequent shots. How do you know which one is "correct" or "accurate" or whatever word you want to use. You mention calibration. How is this accomplished? |
| I am a life long reloader(40+ years) and tinkerer :) With that said, see the last line in my post above. I don't find that any of the units out there are 'on' from day to day. The most reliable way to tackle at least one, and maybe the most problematic variable, is to use screens/units with a light source. The other gun cranks in my life are using the Beta and Gamma Chrony units with the light source and getting more consistent results with fewer errors. It's a pain, as AC power is needed, so he brings his little quiet generator. I think there is a battery pack set up out there made for just this use, but can't find it at the moment. Again, if recoil or a change in the shooting position moves your weapon from being aligned centered over the sensors, your readings will be even less consistent. The Chrony is a prime example. Laboratory results are not possible at the range, but the data we can collect is still valuable. Five sessions with the same match load....just use the average of those numbers for a pretty close look at your load and the work you put into it :) |
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I think there are potential situations where you can indeed get stuck regardless of which chronograph you use. For example, even using both the Oehler and the Alpha Master Chrony together, I could potentially get three different numbers and without an ability to shoot a "Standard” round of exact known velocity for the current conditions, it is impossible to know which if any are correct. Of course, this assumes the worst case which is like asking if you are driving a car and the brakes goes and your accelerator is also jammed down, then you are definitely sunk – no doubt. Part of the rationale for paying a lot more for the Oehler to get the duel read is that you are getting a much higher quality instrument that can check on itself. My Alpha Master Chrony just came back from the factory calibrated and so the idea is to see how they do. There is absolutely no guarantee that it will all work perfectly but short of doing your best, which I think I am doing here, the only other thing to do is to throw my hands up and quit. FWIW, I do not plan to use both instruments together all the time, just testing them at the start to see how things work out. I will use only the Oehler and keep the Alpha Master Chrony as a backup. |
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The word "if" is not presumptive, it is conditional. You are evading the question. You chronograph one shot. The readings are 2730 and 2796 and the two instruments continue to differ by approximately that amount on subsequent shots. How do you know which one is "correct" or "accurate" or whatever word you want to use. You mention calibration. How is this accomplished? These are the real issues, are they not? I would be much happier if my PACT chrono data showed only that 2% difference and would stay there. If it were consistently erroneous, I wouldn't be so unhappy with the instrument. As it is, it is highly variable, almost to the point of providing meaningless information - nonrepeatable from hour to hour and certainly from day to day. How does one calibrate an instrument? I am wanting to calibrate the electronic box on a bench top with a signal generator output going to the start and stop sensor inputs. If the box is decent, I will feel fairly certain the trouble is with the skyscreens (which is where my intuition has me now). |
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Trollslayer – how do you position your chrony? I ask because it is generally not a easy thing to do. What I have found is that by using a laser inserted into the barrel, I can position the path of travel of the bullet pretty accurately at the optimal position for the sky screens. It also helps me from shooting them but that is another separate issue. |
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Even the best chronographs are not 100% accurate when it comes to long range dope. This is why it is absolutely necessary to "true" rounds after getting an estimated firing solution for a known distance if you intend to be able to make first round hits at distances over about 500m. A short summary of my SOP (which I was taught in several precision rifle classes, and which you will also see a version of done in the Magpul precision rifle DVDs) is as follows:
Zero rifle. Measure zeroing shots over chrono (after getting rough zero). Record average of at least 5 shots. Compute "dope" with ballistic software (I've use ATrag, Bulletflight and iStrelok and all are within the same click out 1000m) using data from chrono Shot at 1/2 MOA target at distance (generally about 7-800m with 223 or 308). I use a sporting clay. If necessary, have an observer spot impacts. Measure distance from impacts (assuming consistency) to target. Disregard wind. Only measure elevation difference. Adjust so that elevation is correct and confirm (I dial elevation to make these adjustments). If you want, you can also apply a wind call try to bust the clay. Again, however, elevation is all that we are looking for. "True" your software to reflect the actual firing conditions. ATrag will do this for you, but you can do it easily through the other apps by simply adjusting your initial velocity until it provides you with the correct dope you just established. Save this into your software, and complete a range card for future engagements (assuming similar environmentals). Note that this works best with established and known loads (e.g. MK262 or MK118LR) where there is confirmed BC data available. This is somewhat more tricky to do with loads with potentially dubious BC's, but you can refine at additional distances and I have never experienced any issues adjusting strictly velocity within my engagement distances (within 1000m utilizing a 308). This includes truing of bullets of completely unknown BC (specifically, I was taught this technique using Privi 165 SP for which there is no published data available. In case it interests anyone, you can use 2520 FPS and .4 BC out of a 16" gas gun to excellent effect out to 800m). You do potentially run into issues with wind, but getting a first round hit in the wind with a completely new load that you don't have any "feel" for at distances beyond 600m is very difficult to begin with and I applaud anyone who can do it through software alone (hint: you have to measure the wind through observation before the software can even begin to help. Once you can measure the wind by observation, you no longer need the computer). |
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Again, nothing is 100% accurate, but reasonable accuracy is what is needed. The problem with a single chronograph is that it is hard to know when it is off since it is only one number and could just as well be your reloading technique. My chrony was indeed bad and it has been fixed (I hope), having a failed chrony has taught me to not trust using a single one. My own feeling is that my chorny has been fixed and I will verify it with my Oehler. I will then pack it way for use as a backup or as a standard to compare with my Oehler should there be a problem. |
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Again, nothing is 100% accurate, but reasonable accuracy is what is needed.
The problem with a single chronograph is that it is hard to know when it is off since it is only one number and could just as well be your reloading technique. My chrony was indeed bad and it has been fixed (I hope), having a failed chrony has taught me to not trust using a single one. My own feeling is that my chorny has been fixed and I will verify it with my Oehler. I will then pack it way for use as a backup or as a standard to compare with my Oehler should there be a problem. For load development and such, you are absolutely correct and I regularly use a chrono for number of functions while working with different loads. For shooting at distance, however, I would caution you not to rely on chrono data regardless of source. |
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Quoted: We are on the same wavelength. I only use the chrono data as a starting point for distance shooting. What I do is to take my 20 rounds from my 600 yard practice and input their position into the On Target software to find the average POI and use that to determine what the correct MV would be in my NightForce Ballistic calculator to get the correct elevation sight correction. For BC, I use the numbers from Bryan Lutz. Quoted: Again, nothing is 100% accurate, but reasonable accuracy is what is needed. The problem with a single chronograph is that it is hard to know when it is off since it is only one number and could just as well be your reloading technique. My chrony was indeed bad and it has been fixed (I hope), having a failed chrony has taught me to not trust using a single one. My own feeling is that my chorny has been fixed and I will verify it with my Oehler. I will then pack it way for use as a backup or as a standard to compare with my Oehler should there be a problem. For load development and such, you are absolutely correct and I regularly use a chrono for number of functions while working with different loads. For shooting at distance, however, I would caution you not to rely on chrono data regardless of source. But it would be nice if the numbers agree better, thus one reason for the better chrono. |
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LOL! I have not shot my chonograph in a long while but I carry spare skyscreens in the kit (always).
I do a very decent job of set up but don't use a laser. I have a tripod with all sorts of tilts and elevation adjustments. It takes about 5 minutes, no more than that. The CED guys describe a single-piece, rigidized, fold-down box in their user manual. You use it in lieu of the skyscreens. I believe that will help quite a bit but have not yet built it (too busy these days). |
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LOL! You know what they say about shooting chronies – it’s not a matter of if but when? I am very careful and did not think it would happen to me but I have shot my chrony a couple of times even after carefully looking down both screens to line up with the barrel but it happened….
The good thing is that on both occasions, I only shot the supporting sticks and so this clues me on to the fact that I really don’t know exactly where the round goes when it travels over the sensors. The Laser really works well as it allows me to position the bullet’s path directly over the sensor and at the correct prescribed height. The only drawback is the danger of leaving the laser in the barrel… To avoid a problem, I always push the bag the laser is normally stored in into the trigger guard. That way even if I forget, I will remember when I try to pull the trigger..... |
| I like to chronograph all my workup loads. I also like to chronograph known loads to help get data for my ballistic calculator. That said, I use my chronograph almost every range session. I always hated going to the range and getting everything set up just right. Then, if the sun wasn't cooperating you did all that setup for nothing because I couldn't get good MV data. I have switched to the magnetospeed chronograph and I couldn't be happier. Setup takes a few seconds and you don't have to worry about the sun or cloud cover. There are some instances where the magnetospeed won't work but, I rarely run into those situations. The only drawback is that it attaches to the end of your barrel. I haven't noticed a huge POI shift but, I'm sure it's a possibility with some firearms. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? It's definitely a consideration. I haven't noticed much of a POI change with it attached to my barrel. I've only used it on my heavy barrel Remington 700. I haven't had it that long and I'm still playing with it but, so far I like it. It's surprisingly light weight. |
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Quoted: Quoted: It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Of course that is true, but when you are working up a load, you are looking for both accuracy and tight MV if you are doing precision reloading for long range shooting. So if your chrono affects where your node is, it does not matter how well it reads the MV, when you get done working on the load and take the chrono off and your node is now in a different powder range, where would you be? Not saying this actually happens but as BADZ06 says, it’s a consideration which means it is possible. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. |
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Quoted: Quoted: Quoted: Quoted: It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. When you work up a load i.e. change anything to do with reloading, and there is a huge long list of things, all these things can affect your node and therefore accuracy and MV, you want to get both at the same time when you test because it is not a onetime thing but a continuum meaning it usually takes a lot of work and many many sessions ..... What you are suggesting is possible but that would mean you would load up and shoot twice the number of rounds you would normally need. NO ONE I know who does this would go that route – it’s DOA before you start. |
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Quoted: It's funny what you said about the picatinny rail, was thinking exactly the same thing.Quoted: Quoted: It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel.  |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. This is kind of the approach I'm taking with it. I normally start working up loads with the magnetospeed attached and do most of my load testing. Once I find a load that is grouping good with it attached, I will take it off the barrel and verify that I'm still getting good groups. So far, I have not noticed much if any change in impact with the chronograph attached. Note that I have not specifically tested to see if there is a POI change but, through my regular load testing I haven't noticed any big changes. I kind of look at it the same way I do when I shoot with a suppressor. I may get a POI change when I attach a suppressor to my barrel but, if I was getting good groups without the suppressor I still get good groups with the suppressor even if they are hitting a little different spot on the target. Now, I'm not saying that it can't change the barrel harmonics and throw things off. All I'm saying is that I haven't specifically tested for that and I haven't noticed any drastic changes in my groups. I haven't tried this thing on a pencil barrel yet. It could have a dramatic effect on accuracy if attached to a thin barrel. I may try to get out to the range this weekend and test it with my LW DD upper. |
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Thanks for all the response,s fellow shooters.
The reasom I ask this question?.. I did the usual about 10 yrs ago and shot my 1st Chrony....then.....I purchased another. It basically jsu stop,d working from one day to the next, so I basically would borrow an old chronograph from a fellow shooter once I did my R&D on load development and got my good/tight/consistant patterns at 100, (finding the rifles sweet spot).... I would then record the fps for record keeping and more importantly, for ballistic calculation (dop)... I recently purchased a used Chrony which works great, but I wonder about the readings Im getting, to me, the readings are comming back relatively slower, possible about 150/200 fps slower. W I know what Im gonna have to do and thats to borrow my friends chrongraph and test it against the one I just purchased. To me, mines reading slower...or...is his reading faster?......... can chronograph,s be calibrated???????? |
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I would suggest that you borrow your friends chrony and arrange them in series and shoot through both of them at the same time. Do at least 5 rounds and record the value and you should be able to figure out if they are indeed different or not and whether it might need fixing. My understanding is that chronographs can indeed be calibrated. As mentioned in my post, I send mine back to Shooting Chrony Inc and it came back according to the technicians notes "calibrated”. So it can be done but just not by the end user. Whether yours can be calibrated depends on who made it and whether it is still supported. Mine was 2.5 years old and was still under warranty (3 years). I would call your manufacturer and ask them, that is your best bet. |
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Thanks for all the response,s fellow shooters. The reasom I ask this question?.. I did the usual about 10 yrs ago and shot my 1st Chrony....then.....I purchased another. It basically jsu stop,d working from one day to the next, so I basically would borrow an old chronograph from a fellow shooter once I did my R&D on load development and got my good/tight/consistant patterns at 100, (finding the rifles sweet spot).... I would then record the fps for record keeping and more importantly, for ballistic calculation (dop)... I recently purchased a used Chrony which works great, but I wonder about the readings Im getting, to me, the readings are comming back relatively slower, possible about 150/200 fps slower. W I know what Im gonna have to do and thats to borrow my friends chrongraph and test it against the one I just purchased. To me, mines reading slower...or...is his reading faster?......... can chronograph,s be calibrated???????? Where in Texas are you located? |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. When you work up a load i.e. change anything to do with reloading, and there is a huge long list of things, all these things can affect your node and therefore accuracy and MV, you want to get both at the same time when you test because it is not a onetime thing but a continuum meaning it usually takes a lot of work and many many sessions .....
What you are suggesting is possible but that would mean you would load up and shoot twice the number of rounds you would normally need. NO ONE I know who does this would go that route – it’s DOA before you start. What he suggested might work for him but for me it would be a waste of components and time. I could just load up 10 rounds and get both results at the same time with a regular chronograph. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. This is kind of the approach I'm taking with it. I normally start working up loads with the magnetospeed attached and do most of my load testing. Once I find a load that is grouping good with it attached, I will take it off the barrel and verify that I'm still getting good groups. So far, I have not noticed much if any change in impact with the chronograph attached. Note that I have not specifically tested to see if there is a POI change but, through my regular load testing I haven't noticed any big changes. I kind of look at it the same way I do when I shoot with a suppressor. I may get a POI change when I attach a suppressor to my barrel but, if I was getting good groups without the suppressor I still get good groups with the suppressor even if they are hitting a little different spot on the target. Now, I'm not saying that it can't change the barrel harmonics and throw things off. All I'm saying is that I haven't specifically tested for that and I haven't noticed any drastic changes in my groups. I haven't tried this thing on a pencil barrel yet. It could have a dramatic effect on accuracy if attached to a thin barrel. I may try to get out to the range this weekend and test it with my LW DD upper. I'm not worried about POI shifts, those I can deal with it's the group sizes that would be my concern. The magnetometer seems like a good idea but if I am going to pay $250 for the damn thing it better work better than my $110 Chrony. I'll just wait for others to try them out a little more before I spend my money on it. |
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It is an interesting instrument but to me not proven yet. For example, what about effects which affects harmonics and where the nodes are? Seems like anything that attach to the barrel would affect these? Neither of those affects velocity, only accuracy. Which might be a problem if you are trying to find an accurate load. It might shoot one load very accurately with the magnetometer attached but then when you remove it the groups might open up. I am considering buying one but haven't made up my mind yet. It would be nice if they had some sort of attachment that would let you mount it to a picatinny rail instead of to the barrel. I must be simple minded or something. Don't chronograph the cartridges you shoot for accuracy, but chronograph a different batch (from the same loading session) of that load. What am I missing here which makes it so complicated? Load 20, shoot 10 for a group and chronograph the other 10. This is kind of the approach I'm taking with it. I normally start working up loads with the magnetospeed attached and do most of my load testing. Once I find a load that is grouping good with it attached, I will take it off the barrel and verify that I'm still getting good groups. So far, I have not noticed much if any change in impact with the chronograph attached. Note that I have not specifically tested to see if there is a POI change but, through my regular load testing I haven't noticed any big changes. I kind of look at it the same way I do when I shoot with a suppressor. I may get a POI change when I attach a suppressor to my barrel but, if I was getting good groups without the suppressor I still get good groups with the suppressor even if they are hitting a little different spot on the target. Now, I'm not saying that it can't change the barrel harmonics and throw things off. All I'm saying is that I haven't specifically tested for that and I haven't noticed any drastic changes in my groups. I haven't tried this thing on a pencil barrel yet. It could have a dramatic effect on accuracy if attached to a thin barrel. I may try to get out to the range this weekend and test it with my LW DD upper. I'm not worried about POI shifts, those I can deal with it's the group sizes that would be my concern. The magnetometer seems like a good idea but if I am going to pay $250 for the damn thing it better work better than my $110 Chrony. I'll just wait for others to try them out a little more before I spend my money on it. I can tell you this about the magnetospeed...I don't get errors with it. What prompted me to buy the thing in the first place was a day at the range where there was moving cloud cover and my Chrony wouldn't work for crap. I fired around 100 rounds that day and got maybe 25% of the MV data I should have got. My Chrony just couldn't get good data. Not to mention if there is someone next to me at the range with a muzzle brake it really messes my Chrony up. I no longer have those problems. I'm not saying I'm going to retire my Chrony but, this thing is pretty darn convenient. I'm not seeing any of my groups opening up while using it so far. There are obvious problems with using it. It's not going to work with some handguns. It's not going to work with a suppressor attached to your barrel. There needs to be an attachment so you can connect it to a free float rail. It won't work with some muzzle brakes. That's why I still have my Chrony. The magnetospeed is just another tool in the toolbox of things we can use to produce quality hand loads. ETA...Here is a link to a review on snipershide. My experience with the magnetospeed is essentially the same as his. Link to snipershide |
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Thanks for all the response,s fellow shooters. The reasom I ask this question?.. I did the usual about 10 yrs ago and shot my 1st Chrony....then.....I purchased another. It basically jsu stop,d working from one day to the next, so I basically would borrow an old chronograph from a fellow shooter once I did my R&D on load development and got my good/tight/consistant patterns at 100, (finding the rifles sweet spot).... I would then record the fps for record keeping and more importantly, for ballistic calculation (dop)... I recently purchased a used Chrony which works great, but I wonder about the readings Im getting, to me, the readings are comming back relatively slower, possible about 150/200 fps slower. W I know what Im gonna have to do and thats to borrow my friends chrongraph and test it against the one I just purchased. To me, mines reading slower...or...is his reading faster?......... can chronograph,s be calibrated???????? Where in Texas are you located? southwest texas . elevation where i shoot at is @ 4400 |
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I would suggest that you borrow your friends chrony and arrange them in series and shoot through both of them at the same time. Do at least 5 rounds and record the value and you should be able to figure out if they are indeed different or not and whether it might need fixing.
My understanding is that chronographs can indeed be calibrated. As mentioned in my post, I send mine back to Shooting Chrony Inc and it came back according to the technicians notes "calibrated”. So it can be done but just not by the end user. Whether yours can be calibrated depends on who made it and whether it is still supported. Mine was 2.5 years old and was still under warranty (3 years). I would call your manufacturer and ask them, that is your best bet.
roger that..... i do infact plan on setting them up in series and see what gives. its an older chrony f1 from what i can tell. the chassi is colored red (alpha?) |
[ARCHIVED THREAD] - Chronograph accuracy (Page 1 of 2)
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