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More poor chrono data

Discussion in 'Reloading' started by XDRoX, Mar 20, 2010.

  1. XDRoX

    XDRoX

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    Well first off, thanks for putting up with all my troubles. As you remember my chrono data last time sucked. It was all over the place. Well I got back on the horse today tried again. This time here's what I did:

    Used same brass (R-P)
    Weighed each charge by trickling into scale
    Weighed bullets (they weighed all over the place, but I got 10 that matched)
    Didn't adjust the set die between rounds.
    Stood 25 feet from chrono
    Sun was directly over head
    80 degrees out
    Elevation 3281

    Results (thanks to AJE for the Excel spreadsheet)
    [​IMG]
    So obviously my data once again sucks. I think I can rule out my reloading, as I was so careful while doing it. The only thing that I can guess is that my chrono sucks, or I'm not shooting where it reads.

    Here's an interesting thing that happen today as well. While shooting some 45 that I loaded the data read:
    1033
    1062
    783
    796
    800
    800
    800
    807
    1038
    1043

    This makes me think that maybe the chrono is just really sensitive to where I need to place the bullet. Maybe I got lucky in shot placement with the middle 6 rounds, as they look to be accurate.

    Are chrono's usually sensitive to where the bullet must pass through? Because honestly, at 25 feet the chrono was lucky to make it home. I don't think I could place shots better than I was.

    Well, what say you guys?
     
  2. GioaJack

    GioaJack Conifer Jack

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    Well your problem is obvious... you're shootin' from horseback, unless you're Annie Oakley that ain't never gonna work. You're lucky you didn't shoot the horse.

    Were you using your defusers? Try standing around 18-20 feet away, put you rounds directly over the center of the chrony, under the defusers.

    If you're not confident in your shooting ability take a girl with you... that way if you do shoot the chrony at least it won't be a wasted trip.

    Jack
     

  3. Myke_Hart

    Myke_Hart Handloader

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    I know some folks on here told you that 25 feet was ideal to chrono but I think that is nuts. All you are going to do is shoot the chrono.

    I chrono handguns and rifles at 8 to 10 feet and maybe 15 feet at the most. And I have exploded my chrono at this distance 5 times.:embarassed:
    I never have a issue with muzzle blast.

    Bring that chrono in because you want muzzle velocity and not a dead chrono. Let the chrono cables be your guide, they should only be around 20 feet long.

    You need to chrono factory loads to get an idea if your chrono is functioning.

    Here is what I do. Chronos can be sensitive to light, heat, IR, and all sorts of stuff. Sooo...

    I always take some winchester white box with me and run 5 or so rounds thru the chrono first. This should give you a extreme spread of no more than 100.
    If you get more I would suspect you have a chrono or daylight issue (too bright or too dark) or a bad chrono.

    Then run your loads thru..

    If the white box gives stable readings and your loads give sporadic readings then you know what is wrong. Else, you still know whats wrong and you can send your chrono back.

    Hope it helps.:supergrin:
     
    Last edited: Mar 20, 2010
  4. ecmills

    ecmills I shoot guns.

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    Sell that chrono.

    If you're using a shooting chrony, we have found the problem. I hate the damned things. I have one sitting on the shelf in the garage that hasn't come out of the shelf since the day I bought my ProChrono Digital.

    I am a huge fan of the ProChrono. Short of a CED Mark2 ($$$) nothing is more consistent or tolerant of bad lighting and weird positions. Using the indoor light setup, I've clocked a rubberband in my living room. At night. And the chrono was only $100.

    I stand 10 feet from the unit. The 1000+ fps velocities are the only ones I'd trust in that 9mm sample. A 700fps 9mm 115gr will not cycle most factory pistols reliably.
     
  5. fredj338

    fredj338

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    Must be a Chrony! The chrony line has crappy screens, sorry guys, that is just the truth. The shot must go directly over the screen, no higher than 8" or readings start getting funny or missed entirely. SHooting that close to the screens is why so many guys shoot their Chrony. The CED screens are much better, the Oehler the best. I set the screens up 20ft from the bench on a tripod, shoot thru the screens for accuracy & collect vel data too. I very seldom get an eroneous error.
    Buddy & I set up a Chrony, CED & Oehler back to back to back. Shot loads thru them. The Chrony missed or errored more than 50% of the shots, the CED only 3-4% & the Oehler none. The Chrony was at 15ft, the CED 18ft & the Oehler (best screens) at 21ft.
    Try putting an 8"sq piece of cardboard in front of the screens. Put an aiming point dead center right at the top of the cardboard. That should get you decent readings. Another trick, put a piece of trasnlucent scotch tape over the screen slots. This helps keep reflections from tripping the screens (used to do this w/ my crappy PACT screens).
     
    Last edited: Mar 20, 2010
  6. dakrat

    dakrat

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    25 ft is way too far. most chronos suggest 10ft for pistol. each chrono is different, read the manual.
     
  7. rg1

    rg1

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    I agree that 25ft. is not necessary and will lead to hitting your chrono parts. Shooting your 9MM and 45's should cause no issues at 8-10 feet. Only other thing I'd check is that your bullets are being held tightly in your brass cases. A poorly fitted seated bullet that is not held tightly in the case can cause erratic velocities. Check your loaded rounds by trying to push the bullet further into the case with thumb pressure and also by pushing it against the side of your bench. If you can push the bullet further into the case "easily" then velocities will be erratic. A 22 rimfire pistol or rifle is a quick and inexpensive to check chrono readings.
     
    Last edited: Mar 21, 2010
  8. Myke_Hart

    Myke_Hart Handloader

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    I forgot to mention I use the CED M2 and never have any issues, which doesn't help the OP but...

    My opinion is the closer you can get to the screens the less likely you are to shoot them.

    This is direct from the CED M2 manual page 6 for those that may claim we are shooting too close.

    Link to the manual
    http://www.cedhk.com/shop/product_attachments/CEDM2ManLayout.pdf

    * Position the tripod approximately 7 to 10 feet in front of your shooting position for pistol use and 10 to 12 feet for high powered rifle use.
     
    Last edited: Mar 21, 2010
  9. XDRoX

    XDRoX

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    :rofl:
    Thanks guys for all the info and ideas. As guessed it is a chrony and I'm starting to wish I would have shot it. I'll try it a few more times standing closer with better shot placement and see if that works. If not, I'll shoot it.
     
  10. Colorado4Wheel

    Colorado4Wheel

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    If you bought it from Midway you have 90 days to send it back. Return it and get a CED M2. Or at least exchange it for another of the same brand. Like I said in the last thread we don't shoot from that far either.
     
  11. WiskyT

    WiskyT Malcontent

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    Okay here's the deal. You have now done everything to rule all other variables. Your chrono is defective. Shooting farther away can only help, and you did that.

    The Chrony brand is touchy, but when used within their touchy limits, they give good data. Yours doesn't because it is defective. Unless you need new reading glasses send it back.

    To those who think 25 feet is too far, based on what? Many bench resters use their chronos at 300+ yards. The Chrony brand chrono is sensative to muzzle blast, period. For the grand total of ZERO dollars and effort, the OP moved his chrony back a few feet and in his case it didn't help. I don't doubt that other more expensive brands are less sensative and can be used closer, but there is no advantage to using the chrony closer, we're talking about 10 feet more which aparrently is as far as some people can shoot:upeyes:

    I wasn't going to bother mentioning it before since there was no harm in the advice that was given regarding reloading technique, but minor fractions of a grain in powder and bullet weight, thousanths of an inch in crimp and other bull**** like that aren't going to give you a high of 1050 and a low of 850. The only things that can cause spreads like that are eating peyote while measuring your powder charges, the chrono being to close, or the chrono being defective.

    You have ruled out the ammo and the chrono set up, it has to be the chrony itself.
     
  12. Colorado4Wheel

    Colorado4Wheel

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    I agree, it was worth a try. I would still rather have a chrono that did not require being that far away from the pistol. Eventually at that distance, with a pistol, your going to start hitting screens or worse the chrono. Get a better chrono and save the agravation.
     
  13. XDRoX

    XDRoX

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    I'm going to experiment with a BB gun today in my backyard. I'll report back, but probably I'll just return it. I'll tell you one thing. I'm a way better shooter since I got the thing. After I was done messing around with the chrono yesterday I had some fun plinking. I was hitting golf balls and beer bottles at 30 yards.
     
  14. shootingbuff

    shootingbuff Millennium Member

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    Seemed not to have posted so I posted twice
     
    Last edited: Mar 21, 2010
  15. shootingbuff

    shootingbuff Millennium Member

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    First to not getting side tracked on the chrony comments.

    it sounds like it could be your crimp and or you are belling the brass to much and the bullets are falling into the case. Or even an inconsistent stoke in setting and belling the case.

    Don't waste your time with the same brass or weighing your bullets unless you are shooting one hole groups at great range.

    Now to the chrony comments. They may not be the best but with mine and the 3 folks I know at my old club our chronys are near dead on with each other. One day I put mine and a buds back to back. we can take the same batch of loads in the same conditions and get the same results.

    Now I don't have stock in chrony and I think they work. The problem is the gent was looking for answers. Yes it could be his chrony but more likely and easier to trouble shoot is his reloading practices.

    BLUF check the OAL and your crimp. Ensure you operate the press by bottoming out the stroke up and down.
     
  16. fredj338

    fredj338

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    I can guarantee that you put your screens 8ft form a magnum rev you get poor readings & 12ft for a magnum rifle & you can actually damage the screens w/ the blast. Trust me, been using a chronograph since they had paper screens, no closer than 12ft for anything but 22lr & 20ft for rifles. If you can shoot straight, you'll never hit your screens/chronograph. I've seen guys testing vel @ 100yds w/ their chronographs.:dunno:
    Yes the Chrony line CAN be accurate. It our back to back ot back tests, when the Chrony DID get a reading, all the chronographs were within 10fps of each other. It's just the Chrony missed more shots ro gave more errors, why, poor screen quality. If you ever get a chance, look inside a set of Chrony screens & compare w/ CED or Oehler, no comparison. They are tiny, the shot must be placed precisely over the center for best results. BTW, all the Chrony line use the same screens so buying the higher priced one will give the same results.
     
    Last edited: Mar 21, 2010
  17. XDRoX

    XDRoX

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    Thanks for the comments. I'm 99% sure that my rounds are good. I've researched almost every aspect of reloading, so I'm pretty sure they're good. My crimp measures .377" - .378" on every round, and I am hardly belling the brass at all. Just enough to get the bullets in. Also, I'm using a SS Lyman press so it's very easy to tell whether I'm getting a full stroke.

    More interesting data. I just tested the chrony out back with a BB gun. Here's the results:
    382
    370
    368
    368
    386
    381
    375
    368
    376
    378

    That's a SD of just over 6FPS.

    More interesting things:
    The chrony read "ERROR" if I shot above 6" of the screens or if I was off to the side a little. Yesterday while shooting in the mountains it never read "ERROR," not even once. And there was no way I was getting every shot in the correct spot.

    Could it be that the chrony works on BB's but not bullets?:dunno:
     
    Last edited: Mar 21, 2010
  18. fredj338

    fredj338

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    Doubtful, a projectile is a projectile. Blast is the only diff. As noted, a piece of cardboard in front of the first screen would reduce the blast as well as placing it at lest 12ft away. But as you noted, shots have to be pretty precisely placed over the center of the screen. I'm betting you've got one or more bad screens. Also make sure the unit is completely open, even a slight diff will throw the measurements off.
     
  19. WiskyT

    WiskyT Malcontent

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    The reason people shoot their chornographs is because they let their eye drift to the chrono as they break off the shot. Put a target behind the chrono with the bullseye in the sweet spot and MAKE SURE you concentrate on the bullseye. If you are going to hit your chrono at 20 feet, you'll hit it at 10. Long range shooters test the ballistic coefficient of their bullets by chronoing them at long range and comparing it to the muzzle velocity. This allows them to calculate the true BC of the bullets.

    As far as it working with the BB gun, yes, all chronos have an area where they will read. I don't doubt the inexpensive Chrony brand is more touchy and has a smaller sweet spot, BUT, yours is too difficult to work with. My Chrony has a farily broad area it will read over. That yours doesn't, combined with all of the other issues you are having with it, reinforces the idea that it is defective.
     
  20. Myke_Hart

    Myke_Hart Handloader

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    Is it me or does that bb gun chrony data seem quite low.
    My airsoft chronos that fast. Is that what you chrono'd?

    I have to say that that ES is pretty awesome, I might go back and take a look at your bullets again.