Chronographs

Discussion in 'General Discussion' started by TankGunner, Nov 24, 2011.

  1. TankGunner

    TankGunner Member

    Messages:
    5
    Joined:
    Jul 8, 2011
    I'm not sure if this is the right place to ask this question, so if the site admin feel it should be elsewhere then please feel free to move this post to the appropriate section.

    I wish to purchase a chronograph in order to test and develop my reloaded ammunition for my 17rem, .243 and 6.5X55.

    What I'm looking for is a mid price range chronograph that will give me consistent and reliable data when used in a outdoor environment with natural sunlight. As I only have access to an outdoor range.

    It would need to work with as wide a spread of lighting conditions as possible due to the vagaries of the uk weather.We don't get that many bright, cloudless sunny days during the year. So ideally the chronograph will be able to cope this less than ideal conditions.

    Any recommendations based upon personal usage would be extremely useful. As I need to get my selection right first time as I only have the funds available to buy once.

    Atb

    Stan
     
  2. Broz

    Broz Well-Known Member

    Messages:
    8,637
    Joined:
    Feb 3, 2007
    If he does not answer this post, I would PM site member " Phorwath" He has multipul chronographs in line and has done more testing with them than anyone I know. Chronographs are not all created equal , and I have a few that will lie to me on occation. It was not until I bought an Oehler that I placed any trust in them for important things like ES or a true velocity for a ballistic program.

    I feel I do not have the info you need about your special lighting and this is why I recommend you talk to Paul. He has helped me before and he know what he is talking about from first hand experiences.

    Jeff
     

  3. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,072
    Joined:
    Jun 11, 2010
    Buy a Pact and be done with it. Half the price of an Ohler and the difference in accuracey is little if any.
    gary
     
  4. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,711
    Joined:
    Jan 21, 2008
    I have a Pro Chrono and an Ohler 35. I get just about identical results out of both. For 119 bucks for the PC you cant go wrong.
     
  5. phorwath

    phorwath Well-Known Member

    Messages:
    4,902
    Joined:
    Apr 4, 2005
    If you only had the Pro Chrono, how would you ever know if you were getting reliable data? With the Oehler 35P, don't you get two velocity readings for each shot fired? Which means you have some means of verifying the recorded velocities are valid?
     
  6. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,711
    Joined:
    Jan 21, 2008
    Yes, you do get two readings. Out of several hundred shots, I think I have had the Oehler throw out two or three shots because of too big a difference between the two channels. In these cases, my set up was in broken shade/ sunlight, or a low sun position, but didn't have much choice to change my set up at the range. I likely would have omitted, or be suspect of these readings on my own with any unit. Don't get me wrong, the Oehler is a nice Chronograph and comes complete with very nice stands, printer, a dual channels, etc., but if you use good practices, both work . The thing is, I didn't realize that the Pro Chrono was a good unit until I used the Oehler. I get very similiar results out of both of my units.
     
  7. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,072
    Joined:
    Jun 11, 2010
    I have to give you credit when credit is due! You at least took the time to prove out your ideas, and also find errors that few would have ever known about. But alas I have learned (and in some cases finally remembered) about testing that would make a difference. Well maybe.

    It takes a minimum of three identical items to conduct a test, and set a standard. Of course you only had one of each (not your fault of course). Then you can compair them one to one and develope a standard point. But of course you'd have had to taken out a second mortgage to get this done<g>. And I think you did the best you could do with what you had to work with, so my hats off to you.

    I said Pact because of the cost of the investment alone. I found the difference in accuracey was nill, and in the end one still never knew which one was correct, or if either one was correct. (once again not anybody's fault). I have yet to see any chronograph that I thought was perfect. The mounts and stuff on the Ohler leave a lot to be desired. The distance between the screens on the Pact ae too close in my book. Then the others are a distant third place. If you want an Ohler, then buy one! What I'd rather do would be to try a bunch of them on the sameday at about the sametime. Anyway a quarter of one percent at 3500 fps means very little to me as long as things are constent.
    gary
     
  8. phorwath

    phorwath Well-Known Member

    Messages:
    4,902
    Joined:
    Apr 4, 2005
    Hey, I'm not trying to start any fights. I am just making it evident to the readers that there really is no way to know if a chronograph - any chronograph or velocity recording instrument - is producing good data unless there's at least a second velocity being recorded for each shot fired.

    I 100% agree with your statement that "I didn't realize that the Pro Chrono was a good unit until I used the Oehler."

    I would also 100% agree with this statement of my own creation. "I couldn't have realized that the 'XXX brand and model of chronograph' was a bad unit until I used the Oehler." Which really does call into question the wisdom of relying on any chronograph that only provides a single data point. I have interacted with any number of chronograph users of the Shooting Chrony, as well as other brands/models of chronographs that provide only a single recorded velocity for each bullet fired, that didn't end up with a unit as reliable as yours seems to be. To the point that they've lost all confidence in ANY chronograph velocity data.

    Certainly, how vital it is to know one is recording valid data depends on what one intends to do with the data. What are the end uses of the data? If the intention is to develop accurate average MV data for insertion into ballistics programs to model bullet flight from the muzzle out to the extreme ranges engaged in LRH, and if the goal is to develop hand loaded ammunition that is not only accurate at 100 yards, but will be accurate at 1000 yards because the ES and SD of the loaded ammo is low, then I think a fellow out to have at least two velocity data recorded for each and every shot fired. Which is what the Oehler 35 provides.

    It's possible to do this without purchasing the Oehler 35, as I used to do with two separate chronographs that were both relatively low cost units. I initially used an Oehler 33 and a PACT PC2, run in tandem, to obtain my two velocity points. That was how my eyes were opened. I saw the light - so to speak. After just a short period of use, I began to be able to identify the shots that provided bad recorded velocity over either one, or both chronographs. I had less than $200 in the entire setup. Both chronographs were purchased as older used models and units. And both have, over the years, been proven to be good enough to get the job done when operated concurrently. But neither chronograph, if run solo, were good enough for me. For my end uses of the data. It wasn't until I ran them in tandem, concurrently; obtaining two velocities for each shot fired, that I was able to identify and discard the bad data that would occasionally be recorded. Here's a photo of the skyscreen stand I constructed to hold the skyscreens for the Oehler 33 and PACT PC2.

    [​IMG]

    My impression is that the OP is pretty serious about collecting reliable data. The only way to collect reliable data is to have some means of validating the data. The only way to begin to have any means of validating the data from chronographs is to have a minimum of two data points for each shot fired. I did that on-the-cheap by constructing a skyscreen rail that allowed me to run two separate chronographs concurrently. For those that don't want to, or are unable to, go through this effort the Oehler 35 is the only retail unit for sale that provides two recorded velocities for each bullet fired. Which is why the Oehler 35 is the only single chronograph that I would recommend for any user that requires validation of the data prior to using it to predict 1000 yd ballistics.

    Here's a link to a Thread that provides my experiences with collecting bullet velocity data with the units I've employed over the years. This Thread will provide further explanation of the points I'm trying to make in this Thread, if any reader is interested enough to survive the long read:

    http://www.longrangehunting.com/forums/f19/new-oehler-35p-new-skyscreen-rail-first-test-data-60778/
     
    Last edited: Nov 25, 2011
  9. Greyfox

    Greyfox Well-Known Member

    Messages:
    3,711
    Joined:
    Jan 21, 2008
    Phorwath,

    I have no argument at all. Two readings are better than one, and will give a higher level of confidence in your data. I guess the difference is that I ihave always used any of my chronographs as a supporting tool as opposed to the sole determinant in developing my ballistics information. That includes velocity, ES, STD deviation information. All loads and supporting information is developed using a combination of actual drop data, recorded velocities, and entry into a ballistics program that is verified for absolute reliability. From that verified ballistics program I can then develop my information for different environmental conditions. I will then keep a supply of the specific load used to develop this data on hand. If I change any variable in my load, i always begin by shooting and recording this load first on my chronograph. I can than get a point of reference should there be a change in conditions. Don"t get me wrong, the confidence level possible with the Oehler two channel system. is the reason why I bought it in the first place. I would have to say though that I have had the same successful results in my long range shooting long before I bought my Oehler. I don't believe absolute knowledge of the actual velocity is necessary or even possible considering variables in BC, rifle,conditions,etc. Consistency is much more critical than absolute accuracy in a chronograph. Thus my original point. My Pro Chrono and my Ohler are very consistent. I have used others that are definitely not.
     
  10. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,072
    Joined:
    Jun 11, 2010
    an interesting experiment I did many years back just occured to me, and may have some merit in this converstion.

    I was shooting two 6mm Remingtons that seemed to have chamber that were almost identical. The barrels has similar twists, but one was a sporter and the other was a bull barrel. Even the lengths were the same.
    On both rifles I was plagued with fliers that almost always impacted between the ten oclock and 12 oclock position. I'd shoot four shots and the next one would be a flier (not always in that order). I was loading at the range, and only using five rounds. (the answer was obvious, but just didn't register. I had weighed the cases, and made them as identical as I could. Then I marked the case that shot a flier with a felt tip pen. Sure enough the next flier was that case. Got another case out of the box and loaded it, and the group was right there. Went home an measured all six cases to see how many grains of water they held. The marked case was slightly less in capacity than the others; yet weighed within the 5/10th window.
    Next trip to the range, I brought my chronograph to do some work with a .223. I also brought the two 6mm rifles, and for the heck of it I shot them thru the chronograph. Had forgotten about the odd ball case, and when fired it was a little faster than the others. Not a whole lot but still a little bit. I remembered getting a shot every now and then that was out of the window I was using for my velocity. I then started keeping track of .223 cases that acted funny, and it was the same damned case almost everytime! I started culling them, and my groups got better and better

    Of course there are no bells or whistles to let me know something's wrong with a round going thru the screens, and you just have to do a little thinking. I now set aside any round that seems odd in performance, and then check the case out when I have time
    gary
     
  11. TankGunner

    TankGunner Member

    Messages:
    5
    Joined:
    Jul 8, 2011
    Thanks for the input guys.
    Can not get hold of an Oehler will go with what Gary reckons and get the
    Pact with IR screens.
    ATB. Stan
     
  12. Trickymissfit

    Trickymissfit Well-Known Member

    Messages:
    4,072
    Joined:
    Jun 11, 2010
    I hear a little pro & con on the inferred screens. I may try them with my new Pact, but I'll also have the standard screens incase I don't like them. (note: Pact says the screens are interchangeable and my old ones will work just fine).

    Now I gotta give Paul some credit for making at least one guy put on his thinking cap! Two revisions I'd like to see Pact do; first is to lengthen the distance between the screens to 36" or one meter. Locate them with dowl pins. I just have an idea in the back of my head that a 36" spacing might be better. Secondly, I think Pact needs to make a major change in their system. Make a provision for a third screen incase you want one. Then all of them need to add a device to insert an SD card in there to save all your shooting data. With that you can simply down load the data into your PC for future reference. I also prefer the older light bar better than their new bracket.
    gary
     
  13. gcamp54

    gcamp54 Well-Known Member

    Messages:
    273
    Joined:
    Feb 28, 2009
  14. phorwath

    phorwath Well-Known Member

    Messages:
    4,902
    Joined:
    Apr 4, 2005