24hourcampfire.com
24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
Joined: Jul 2009
Posts: 1,045
Campfire Regular
OP Offline
Campfire Regular
Joined: Jul 2009
Posts: 1,045
Working with load data and trying to understand why predictions are not close to actual.
I'm loading this as pictured but actual velocities are almost 200 fps faster than quickload.
62.5 gr H1000 3246 fps avg 16 ES 8 SD

What am I missing here?




Cartridge : 6.5 mm RSAUM
Bullet : .264, 123, Lapua Scenar GB489 6032 G7
Useable Case Capaci: 65.256 grain H2O = 4.237 cm³
Cartridge O.A.L. L6: 2.795 inch = 70.99 mm
Barrel Length : 24.0 inch = 609.6 mm
Powder : Hodgdon H1000 *T

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 84 49.76 2388 1557 26827 9743 84.3 1.636
-18.0 86 51.00 2454 1644 28687 10134 86.1 1.594
-16.0 88 52.25 2520 1735 30679 10516 87.8 1.553
-14.0 90 53.49 2588 1829 32820 10887 89.4 1.512
-12.0 92 54.74 2656 1927 35124 11245 90.9 1.472
-10.0 94 55.98 2725 2028 37606 11587 92.4 1.430
-08.0 96 57.22 2794 2133 40278 11912 93.7 1.383
-06.0 98 58.47 2864 2241 43165 12217 94.9 1.338
-04.0 100 59.71 2934 2352 46283 12499 96.1 1.294
-02.0 102 60.96 3005 2466 49656 12756 97.0 1.252
+00.0 105 62.20 3075 2583 53310 12987 97.9 1.210
+02.0 107 63.44 3146 2703 57278 13189 98.6 1.171 ! Near Maximum !
+04.0 109 64.69 3217 2826 61589 13360 99.2 1.132 ! Near Maximum !
+06.0 111 65.93 3287 2951 66285 13497 99.6 1.095 !DANGEROUS LOAD-DO NOT USE!
+08.0 113 67.18 3358 3079 71412 13600 99.9 1.059 !DANGEROUS LOAD-DO NOT USE!
+10.0 115 68.42 3428 3209 77019 13667 100.0 1.024 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 105 62.20 3250 2885 65007 12723 100.0 1.111 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 105 62.20 2840 2203 43223 12319 90.0 1.337




The beatings will continue until morale improves
BP-B2

Joined: Jun 2008
Posts: 664
Q
Campfire Regular
Offline
Campfire Regular
Q
Joined: Jun 2008
Posts: 664
First - to be clear - are you saying that you recorded MV's from a load you worked up in QL - or are you just comparing data from QL with data from a reloading manual?

Second - look up "cross sectional bore area" in QuickLoad instructions - then do that. You will have to slug your bore, then measure the number, height, and width of the lands, and your QL results will be more accurate.

Third - double check everything, including case H2O capacity.


Like Sam Houston, I will vote for what is best for ME in 2020.
Texans read their Bibles to find what they want it to say, and are blind to what it actually says...
Joined: Oct 2008
Posts: 7,263
T
Campfire Tracker
Offline
Campfire Tracker
T
Joined: Oct 2008
Posts: 7,263
Not that familiar with QL but I thought it interesting that the data for an increase of 10% burn rate almost matches your velocity exactly. May just be a coincidence.


"When you disarm the people, you commence to offend them and show that you distrust them either through cowardice or lack of confidence, and both of these opinions generate hatred." Niccolo Machiavelli
Joined: Dec 2004
Posts: 14,467
Campfire Outfitter
Offline
Campfire Outfitter
Joined: Dec 2004
Posts: 14,467
There are three fairly easy things you can do to enhance your QL results.

First, setting H2O case capacity is pretty important for getting accurate predictions out of QuickLOAD.

The way I do that is as follows:

1. choose 10, 15, or 20 fired cases at random and find the total weight.
2. calculate the average weight for your cases
3. find one case that is closest to the calculated average by weight and record its weight
4. fill the case with water to overflowing and carefully wipe the moisture from outside the case and weigh and record it
5. the difference between these two numbers will be your case H2O case capacity

When you run QL you can enter your own value value in the "Maximum Case Capacity, overflow" field. Small changes in this parameter can make significant differences in QL result.

Another field that is worth attention is the "Shot Start (Initiation) Pressure" on the powder side of the inputs. Hover your cursor over the field for that value and you'll see an explanation. In my experience and opinion, the value in that field should be increased if and when you seat a bullet any closer to the lands than about 0.010." Increasing the start pressure value by 7200 psi does NOT simply add 7200 psi to the final calculation, it changes up the burn curve entirely and resultant pressures (and by extension, velocities) much more than that.

The third thing: you can play with the Ba factor on the powder side of the input screen. Other powder parameters can be diddled also. That function is enabled by clicking on the icon in the upper left-hand corner of the powder window. Personally, I do not play with that side of the screen much at all---other than the Start Pressure field, occasionally. I just don't find it necessary


Don't be the darkness.

America will perish while those who should be standing guard are satisfying their lusts.


Joined: Jan 2018
Posts: 25
M
Campfire Greenhorn
Offline
Campfire Greenhorn
M
Joined: Jan 2018
Posts: 25
It is easier to put your case on an ACCURATE digital scale, zero it out...THEN add the water. You can get a DIRECT reading that way and not have to mess around with wiping out the water IF YOU ARE CAREFUL. Digital scales are CHEEP so buy a couple, and get a JEWELERS scale as they are the most accurate and buy one that weighs two-three times the total weight of case and water or loaded case...they are more accurate and have a smaller range. READ and UNDERSTAND the fine print to understand the accuracy range...AND use at least two different scales to measure the final total weight as an accuracy check also.

Depending on the case brand you only need to check maybe 5 cases unless you are target shooting for money or fame. I don't bother weighing when I use Hornady, Norma, Lapua, RWS brass as I've found it to be more uniform than almost ALL the phaating around I did in the past trying to get uniform brass for my benchrester/varminting/long range rifles...I think the price of the brass is cheaper also considering all the time I spent messing about getting wet.

QL uses a mathematical algorithm to determine velo... and chrono timers can be WAY OFF especially Chrony's...my beta is usually ≈150 fs faster than my Oehler 33 when compared back to back, i.e., one in front of the other...AND...I've found QL to be way the heck of when working with MANY wildcat cartridges...DON'T TAKE IT'S OUTPUT VERBATIM...it is a PREDICTIVE software program NOT actual data...besides whatever powder/components they used are different than yours.

It is much better to compare YOUR data with several reloading manuals to get an average velo...if yours is higher or lower you need to re-evaluate your loading procedure and components.

I've been using QL since it first came out and use it ONLY for starting load workups for factory AND wildcats(I have many of those). I also have Powley "computers" going back to the very early NON-computer stuff. I DON'T rely on ANY of the predictive software programs any more except for starting loads...the targets tell me everything I need to know after working up to max accuracy.

If you have a factory/commercial cartridge then forget the predictive programs and use reloading manuals and compare the components they use to what you are using and also the barrel length...AGAIN READ THE FINE PRINT, it's full of good data.

Good Luck

IC B2


Moderated by  RickBin 

Link Copied to Clipboard
YB23

Who's Online Now
775 members (10gaugeman, 007FJ, 10gaugemag, 06hunter59, 01Foreman400, 12308300, 76 invisible), 3,011 guests, and 1,252 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums81
Topics1,187,715
Posts18,400,368
Members73,820
Most Online11,491
Jul 7th, 2023


 







Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2024 24hourcampfire.com, Inc. All Rights Reserved.
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.117s Queries: 14 (0.003s) Memory: 0.8133 MB (Peak: 0.8774 MB) Data Comp: Zlib Server Time: 2024-03-29 02:24:21 UTC
Valid HTML 5 and Valid CSS