Need help with Quickload please

Discussion in 'Reloading Forum (All Calibers)' started by calgarycanada, Jun 9, 2018.

  1. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    I have been using quickload for couple of years now. I don’t have latest version because I don’t shoot any new cartridges that I need data for. Also to add I’m not new to reloading and I’m experienced enough to know how to read pressure signs etc.
    I notice Quickload consistently gives me velocity lower than what I get from chronograph. I would like to use program to predict optimal barrel time and hence reduce load development time/effort.
    At first I was using Caldwell chronograph so I thought maybe it’s not that accurate. I just purchased CED and even that one is showing velocities higher than predicted by quickload. About 40-50 FPS higher.
    I have tested this with 3 different firearms(two 308 and one 7mm-08), all 3 using different bullets and powders.
    I have measured and entered correct values for bullet length, cartridge OAL using same bullet, barrel length, measured case capacity(filled to overflow limit).
    If I try to adjust powder burn rate(as suggested by internet to match velocities) quickload predicts pressure to be higher than safe limits for the cartridge, but I believe it not true because I don’t have any pressure signs at all. Primers aren’t flat, no ejector marks, no heavy bolt lift and plus lots of people are running these loads in their rifles, so known good loads.

    For example my 308 load for 200 gr Hybrids
    Bullet I used for data measured at 1.5”
    Cartridge OAL 3.110” with same bullet
    Barrel length 30”(measured)
    Case capacity 56.7(Lapua brass measured average)
    Bullets are coated with HBN so friction proofed, using standard 0.66 number.
    43.8 grains of varget as per quickload should give 2611 FPS at 56323 psi.
    Chronograph consistently shows 2650-2660 FPS(measured at 10 ft)
    Lots of guys I know are running 43.1 to 43.3 to achieve 2650-2660 FPS from this bullet in their FTR rifles. My bullets are coated and OAL is slightly longer so 43.8 should be around 2650ish which is confirmed by chronograph.
    Im getting similar results from 308 loaded with 185 jugs and H4895 and 7mm-08 loaded with 154 interlocks over IMR4895.
    Can one of you gentlemen please run above numbers for 200 hybrids on your end and see what kind of results are you getting?

    Just for those who are gonna say contact Neco, I did send an email to Neco about a week ago and haven’t heard back from them, they are probably backlogged.

    Edit: I have shot 200 at longish range(900) but lost all data during move. Plus bullets are pointed so B.C. is slightly different which makes it little harder to reverse calculate accurate velocity.
     
    Last edited: Jun 9, 2018
  2. Forum Boss

    Forum Boss Administrator

    Joined:
    Sep 9, 2009
    Messages:
    4,054
    Variation of same shot fired over different chronographs can be up to 30 FPS, with 20 FPS common. We tested six chronos on a single rail and saw this. Neither CED nor Caldwell is particularly exact. But even Oehlers can vary.

    Variation of up to 60 fps is possible with same exact load in different barrels. 30 fps difference between barrels is common.

    Lot to lot powder variation could easily be 20-30 fps with 200-grainers in a .308 Win.

    HBN coating can affect velocity in a way that's difficult to precisely quantify (and QL correction factor is not precise -- even the program's creator told me that.)

    QL's model for velocity variation by barrel length is somewhat imprecise, particularly at extremes.

    You are observing a 40-50 fps variable from QL prediction. Honestly, that's not surprising at all. Truly. 30 fps could be your barrel, 20 fps could be the chrono. Add in the correction factors for barrel length and coated bullets and you have a lot of fudge factors. Oh, and powder lot variations.

    Honestly I believe you are over-thinking this if you're worried about the number your chrono is displaying. What's more important than the raw velocity number is ES and SD!

    As for optimal barrel time -- I would just forget about chasing this as some kind of magic number. It's meaningless by itself. The target will tell you what works. To reduce number of load dev shots, find your max pressure and back off half a grain. Compare your speed to the velocity nodes other competitors are using with the bullet in .308 Win with 30" barrel. Play with seating depth. I suspect you can find a good load in 40 rounds.

    Bottom line here is you really can't expect QL to predict much better than 50 fps, particularly with coated bullets, powder lot-to-lot variations, possibility of "optimistic" chronos.
     
  3. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    Thank you sir! That makes sense
     
  4. Hoosier

    Hoosier

    Joined:
    Nov 7, 2008
    Messages:
    65
    Don't forget the ambient weather conditions. Temperature, humidity, and pressure can effect performance. Warm temps can raise the pressure in cartridges and effect velocity and performance.
     
  5. Ned Ludd

    Ned Ludd Silver $$ Contributor

    Joined:
    May 28, 2012
    Messages:
    1,743
    In addition to the potential errors listed above, you also have to consider that the designers of QuickLoad software give you a single preset burn rate for any given powder. Attempting to provide specific burn rates for the thousands of cartridge and bullet combinations available from the pre-set menus simply isn't feasible. And yet, it is beyond question that bullet weight/design and cartridge capacity/shape both affect pressure, which ultimately determines velocity in a given setup. So Neco gives you a single burn rate as determined from experimental combustion data that will put you in the right neighborhood over a range of different cartridge/bullet combinations. Finding the correct specific street address within that neighborhood is up to you.

    As you have no doubt observed by now, starting safely below the charge weight predicted by QL to yield a specific velocity is always a good idea. I typically find my intended target barrel time/velocity for a given combination that is below MAX pressure, then decrease that by another 2-3%. I then load up a few rounds and determine actual velocity via a chronograph. Once at home, I use the fired cases to accurately determine case water volume, plug in the specific atmospheric parameters for the velocity determination, as well as load-specific parameters such as bullet length, case trim length, barrel length, COAL, etc. After inputting all the pertinent information, I will then adjust burn rate (Ba) until the predicted velocity exactly matches the velocity I measured for a given charge weight. At that point, QL has been "calibrated" to that specific setup and further predictions will be much more reliable than when using the factory presets and/or guesses for load-specific parameters, with the caveat that the larger the you make in an input such as charge weight, the farther off the prediction is likely to be. You will find that many of the QL outputs follow essentially linear behavior, whereas the behavior of many variables such as pressure and velocity are actually not perfectly linear. For that reason, the closer your "calibration" load is to where you ultimately end up, the better the predictions within that fairly small range will be.

    Ultimately, I think you'll find QL can be a very useful tool if you start low as a safety concern, "calibrate" the program appropriately for your specific setup, and try to keep the magnitude of changes reasonable (i.e. within a relatively small range of where you likely expect to end up). If the "calibration" is too far off of the final load parameters, you can always update the calibration step using more appropriate values as you obtain more input data. Regardless, QL cannot ever replace the information given on the target or predict it with 100% accuracy. It is merely a tool to expedite the load development process. Like most predictive tools, the better the inputs, the better the outputs are likely to be.
     
    hogpatrol likes this.
  6. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    Thanks for detailed reply. I have all the data needed to calibrate quickload but if I use powder burn rate to match actual velocity, quickload predicts pressure higher than saami specs. As mentioned in OP I’m very sure that I’m not running close to max pressure let alone above max because I don’t have any pressure signs plus my brass has over 10 loadings on it and primer pockets are good still.
    So I was just wondering if it’s glitch in my copy of software or is there another parameter I can adjust to match quickload with actual velocity so I can use it to predict barrel time without big red warning on the screen.
     
  7. Ned Ludd

    Ned Ludd Silver $$ Contributor

    Joined:
    May 28, 2012
    Messages:
    1,743
    Have you tried some of the other features available in QL to setup a specific rifle file and see if that helps? I haven't yet found it necessary to go to that length to get loads to match up, but it might be of use in your case.

    One other thing to consider is that if you're using Lapua Palma brass with small rifle primers, it will take pressures far in excess if the SAAMI max of 62K psi for .308 Win. In fact, I know of people running Palma brass with loads that are likely in the 65-66K psi range, with no apparent pressure signs. So the question becomes are you not getting pressures as high as predicted, or is the Palma simply capable of taking the higher pressures?

    The main reason I believe the pressure values predicted by QL for various .308 Win loads is that I have for years run loads in standard primer Lapua .308 Win brass. When you run loads in the standard brass predicted to be in the 61-62K psi range (i.e. at or close to SAAMI max), it really doesn't last long before the primer pockets are gone, just as you would expect. Pressure signs such as flattened or cratered primers, ejector swipes, and hard bolt lifts are not always the most reliable indicators of pressure.

    I have loaded the 200.20X bullet in Palma brass with both Varget and H4895 (43.5 gr and 43.0 gr). With a 30" barrel and COALs of 3.120" and 3.117", I'm getting ~2640 and ~2660 fps respectively with those two powders. The respective pressures predicted by QL are 60.4K psi and 59.7K psi; both under SAAMI max. As I stated above, regular brass didn't last very long with similar loads, maybe 4-5 firings before the primer pockets began to give out at a fairly high rate. The Palma brass seems to be capable of taking these loads almost indefinitely. So is it that the pressures predicted by QL are off? Or can the Palma brass higher pressure and therefore have a higher max pressure listed? That's not easy to say with any certainty unless you have actual chamber pressure measurements. In standard .308 Win brass, the QL-predicted pressures seem to correlate well with max pressure, but that is not absolute proof of the QL pressure predictions.

    In any event, if you are not able to figure out why your QL pressure predictions are so high, maybe you could post a screen shot of the QL input/output for one of your loads. Perhaps someone may be able to spot something in one of the windows that might explain it.
     
    Last edited: Jun 12, 2018
  8. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    I’m running Lapua large rifle primer brass.
    I’ll upload screenshot sometime today.
    Thanks
     
  9. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    here's a screen shot
     

    Attached Files:

  10. Ned Ludd

    Ned Ludd Silver $$ Contributor

    Joined:
    May 28, 2012
    Messages:
    1,743
    The things I see that might affect the output are:

    1) Is you case trim length really 2.014"?
    2) 56.7 gr case capacity seems extremely high for Std. Lapua .308 brass, but if you measured it and that's what it is, no worries.
    3) Adjust the Varget burn rate for temp., if it was different than 70 degrees

    Frankly, these should only represent rather small incremental differences. Otherwise, there's nothing major that jumps out that's much different than what I use, which suggests to me that one difference might lie in your changing the start pressure to account for coated bullets, which I don't do Are the predictions any better if you use the factory preset value for start pressure?
     
  11. retired

    retired

    Joined:
    Dec 17, 2017
    Messages:
    1,152
    try this
    skip burn rate, and use energy
    kj/kg
    but again it is a TOOL, not a bible.
     
  12. Bart B.

    Bart B.

    Joined:
    Jun 25, 2012
    Messages:
    1,481
    I've shot enough 7.62 NATO proof loads with about 83,000 psi (67,500 cup) with no visible pressure signs in several people's opinions observing fired cases to convince me its a poor method to estimate pressure.

    There's enough tolerances in bore & bullet diameters and powder burn rates to produce well over 50 to 70 fps spread in muzzle velocity for a a given load.

    Quickload reps will tell you not to expect its calculations to be precise as your component lots and barrel are different than they used. To say nothing about the fact that two people usually don't shoot the same stuff and get the same velocity.

    I think the "optimal barrel time" concept or theory is a joke. Especially when the same load shoots sub MOA through 600 yards across different barrel lengths. Chris Long states "The basic resonant (beam bending or “ruler on the edge of the desk”) mode of a cantilevered barrel (beam) made of steel at our typical lengths and diameters is on the order of 500 to 1000 Hz, give or take." In reality, it's usually a few dozen Hz in the 70 to 100 Hz range.
     
    Last edited: Jun 13, 2018
  13. Jennb

    Jennb

    Joined:
    Dec 29, 2015
    Messages:
    72
    I am sure QL is required to show pressures above SAAMI specks as dangerous due to the lawyer up factor. If you load to bolt pressure and then back off as was stated earlier then calibrate QL you will know your max pressure. Please keep in mind outside temps make pressure rise.
     
  14. calgarycanada

    calgarycanada

    Joined:
    Nov 22, 2014
    Messages:
    194
    Thanks for the help guys.
     

Share This Page