In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.

300 Weatherby and Quickload dilemma

lksmith03lksmith03 Member Posts: 1,742 ✭✭✭✭✭
hey ya'll, been a while since I posted.
I recently took the plunge and bought a copy of quickload. On most of my loads, what quickload spits out is pretty darn close to what I've observed with reading primers and Chrony velocities. The exceptions are 44 mag (Probably due to cylinder gap) and 300 weatherby.
The 44mag is probably due to the cylinder gap, and my not properly accounting for it. I plan on trying it in my single shot 44 to see if that gets me on track.

But the weatherby is a totally different animal. My pet load with a 150gr FMJBT, averages 3636fps with an extreme spread of 35fps. (My SST hunting loads chrony the same) using 88.0gr of Reloder 22 (Book shows max to be 90Gr)
I have updated the OAL to 3.58" to match my load, I have measured the case capacity of my brass to average to 105.27gr H2O, and I have changed the weighting factor to .33 to reflect that it is an overbored cartridge, and changed the barrel length to 26in which is what it is.

The problem is that quickload shows that my velocity should be 3371, which is certainly not close to 3636 (IMO). Changed the barrel length to 34" and it spit out 3628 fps, which is close enough in my book. I changed to another load I had chrono'ed (70.0 GR IMR 4064) which had an average velocity of 3620fps but XS of 181 FPS. That is the ONLY change (QL or real Life). QL spits out 3420 FPS, which is still nearly 100fps below the lowest observed velocity.
Both loads are 48-50k PSI according to QL, which I believe because my brass shows no pressure signs.


Any Ideas? Could magnum primers actually cause the velocities to change by 3-400FPS that QL is not accounting for? If so, any ideas on how to account for that on other loads?


Thanks

Comments

  • Hawk CarseHawk Carse Member Posts: 4,320 ✭✭✭
    edited November -1
    Ever chronograph a factory load?
    The first guess is the proverbial "fast barrel."
  • MIKE WISKEYMIKE WISKEY Member, Moderator Posts: 9,750 ******
    edited November -1
    individual barrels can vary 200+- fps with the same ammo. your quickload is just an approximation
  • lksmith03lksmith03 Member Posts: 1,742 ✭✭✭✭✭
    edited November -1
    Hawk Carse wrote:
    Ever chronograph a factory load?
    The first guess is the proverbial "fast barrel."

    Sorta apples and oranges, but I chrono'd 180gr factory weatherby ammo and it averaged 3248FPS, can't remember which bullet, I'll have to find the box but that weight shows velocity of 3150-3250 on the website, so my gun is pretty much right on the money with factory.


    My goal in working up my load was to duplicate factory 150gr velocity with my SST bullets. Evidently the current loadings are different than what was stated on the data I had initially looked at which stated 3600fps with a 150gr bullet. so when I found a consistent load with that weight hitting that velocity I was happy
  • lksmith03lksmith03 Member Posts: 1,742 ✭✭✭✭✭
    edited November -1
    individual barrels can vary 200+- fps with the same ammo. your quickload is just an approximation

    I thought QL would be closer than that, I expected QL to be within 100fps or less. I initially bought it to help me figure out and work up quiet subsonic loads without wasting a bunch of bullets and buying a bunch of different primers to get close. Basically using it to shortlist my potential loads. But really would be nice if it was close for all my calibers I load.
    Probably my newbieism with the program is causing my mismatches, and like I said, most of my loads test pretty close to QL's predictions, just trying to figure out why the one that aren't matching aren't matching, if that makes sense
  • nononsensenononsense Member Posts: 10,934 ✭✭✭✭
    edited November -1
    lksmith03,

    I have posted a reasonable explanation of the discrepancies found in any 'predictive' formulas whether for reloading or other uses. The information below is a simple representation of data and the aberrations found at each extreme.

    Quickload will nail 70-80% of the normal real world loads for most cartridges when using the average powders and bullets. The exceptions are light bullets in large capacity cases and large bullets in smaller than normal cases. These exceptions fall under the smaller sections of the curve as illustrated below.

    You are using ostensibly what is considered to be a 'light for caliber' bullet for your load test. The normal loads would be oriented towards the 180 grain and 200 grain bullets to keep the ratio of powder to bullet weight in the average area.

    Other considerations are the rampant variation in powder lots from time to time. And here is your other problem, Re-22 which is more likely as not to show variations from shot to shot let alone lot to lot. It is not a very consistent powder and can show substantial swings in pressure as well as velocity. This has been noticed enough to not only be reported but resulted in a new formulation known as Re-23.

    The last mention of variations is in the formulation of 'burn rate' which Quickload has an area for. You can adjust those numbers to create your balance based on your chronograph observations.

    Now, two other things I point out just for information sake:

    Chronograph readings are only as good as the source of those readings. Cheap chronographs are useless as a basis for anything. They are simple clocks which record the start of a shadow and the finish of the shadow as it passes over the sensors. Better chronographs require a specific type or angle of light or diffused light to function correctly. Most of time folks just throw up the chronograph and start shooting without regard to the light at all. That's why many of us have switched to the Labradar. But even the Labradar has its quirks and must be set up correctly in order to provide the most accurate information.

    Normal Distributions (Bell Curve): Definition, Word Problems

    Probability and Statistics > Normal Distributions

    Contents:

    What is a Normal distribution?
    The Standard Normal Model
    Normal Distribution Word Problems.
    Normal Distribution on the TI 89 Examples
    What is a Gaussian Distribution?
    Related Articles.

    What is a Normal distribution?

    standard-normal-distribution.jpg

    A normal distribution curve.

    A normal distribution.

    A normal distribution, sometimes called the bell curve, is a distribution that occurs naturally in many situations. For example, the bell curve is seen in tests like the SAT and GRE. The bulk of students will score the average (C), while smaller numbers of students will score a B or D. An even smaller percentage of students score an F or an A. This creates a distribution that resembles a bell (hence the nickname). The bell curve is symmetrical. Half of the data will fall to the left of the mean; half will fall to the right.
    Many groups follow this type of pattern. That?s why it?s widely used in business, statistics and in government bodies like the FDA:

    Heights of people.
    Measurement errors.
    Blood pressure.
    Points on a test.
    IQ scores.
    Salaries.

    The empirical rule tells you what percentage of your data falls within a certain number of standard deviations from the mean:
    ? 68% of the data falls within one standard deviation of the mean.
    ? 95% of the data falls within two standard deviations of the mean.
    ? 99.7% of the data falls within three standard deviations of the mean.


    The standard deviation controls the spread of the distribution. A smaller standard deviation indicates that the data is tightly clustered around the mean; the normal distribution will be taller. A larger standard deviation indicates that the data is spread out around the mean; the normal distribution will be flatter and wider.

    Best.
  • lksmith03lksmith03 Member Posts: 1,742 ✭✭✭✭✭
    edited November -1
    WOW! Very detailed answer.

    I believe that the following sentence answers my question for my load
    "Quickload will nail 70-80% of the normal real world loads for most cartridges when using the average powders and bullets. The exceptions are light bullets in large capacity cases and large bullets in smaller than normal cases. "

    Not sure why, but RL22 had been my most consistent powder with that ctg/bullet combination.
    I've been using the green chrony, which while may not be lab grade, is what I have used on all my loads, and it has been pretty much go or no go on readings. I always use a white paper background even when the day is cloudy and would probably work without it.
    On all the velocities, they seem to be realistic since the ballistic calculators (mainly point blank) have accurately predicted real world drop.

    I guess my 300BLK, I need to add about 20% to predicted velocities, since it is on the other end of the spectrum (heavy for case capacity)

    Thanks for the help
Sign In or Register to comment.