Quick Load Anomaly

[Coolhand]

I would appreciate the expertise of experienced QL users. I am making this request on behalf of a mate who is perplexed by QL.
My buddy plugged in to QL a load from the ADI Loading Manual for the .270 Weatherby Mag, where it lists as the max load for a 150 grain projectile using AR2217 & a 150gr bullet as 79 grains MAX- MIN 75 grains, however QL says of the MAX & MIN as suggested in the ADI book " DANGEROUS DO NOT USE !"
QL says the MAX of 79 grains is a 115% fill. What are we missing ?

And as an aside , to all those forum members who had relatives take part in the Battle of the Coral Sea, as I did , thank you for your sacrifice, and for those who did not return;

They shall grow not old, as we that are left grow old:
Age shall not weary them, nor the years condemn.
At the going down of the sun and in the morning,
We will remember them.

Lest We Forget.

regards
Mike.

 

[wapiti25]

Thank you for your service. I'm a Viet Nam vet and understand some of what you may have gone thru, I was there during the TET offensive and we were over run.

 

[jlow]

For pressure predictions, you should only start looking at QL numbers after you have put in your specific case volume for the brass you are using (vs. the default case volume which can be pretty far off), and your rounds specific COAL. Both of these significantly affect case volume which in turn affects chamber pressure for any load.

 

[Coolhand]

For pressure predictions, you should only start looking at QL numbers after you have put in your specific case volume for the brass you are using (vs. the default case volume which can be pretty far off), and your rounds specific COAL. Both of these significantly affect case volume which in turn affects chamber pressure for any load.

Thanks Jlow , I dont have a copy of QL and my buddy is forum shy !! I will be sure to pass that on .

regards
Mike.

 

[Nvreloader]

Thank you both for your service, another Nam combat vet here,
173 Abn, 2/503 "Recon", II Corp, 67-68,
Dak to, Kontum, Pleiku were my stomping grounds, on the border.

Tia,
Don

 

[Nvreloader]

+ what Jlow said,
also get the correct length for your bbl length,
QL has lots of tweaks that can be use to match the loading.

Tia,
Don

 

[dewey7271]

Have your friend check what the default pressure setting on his version of QL is for that cartridge. The defaults are occasionally off by a bit. Easy to change the number to an actual pressure SAAMI lists. It's the top left box with the basic data inputs. COAL, bullet, cartridge, barrel length etc is in that box.
Second, COAL makes a pretty big difference in the output.
Then you need actual cartridge capacity from some fired cases.
Then some Chrono numbers from 5-10 shots of the same load.
Next, once you get that set, go to the box to the right of your basic inputs, it's where you put your powder choice.
Push (depress) the button just to the left of the selected powder. This allows changing the inputs in that box.
At the bottom of that box enter your load in the grains of powder box and click the button to calculate.
In the box below the powder box you'll see the outputs on that particular load. Look at the velocity. If it's lower than your Chrono results go back to the powder box above and find the line that says "Ba" which is the powder burn rate. If your chrono result is higher, increase the Ba and calculate. Keep increasing until the velocity (speed) matches what you are seeing. Click on the shortcut bar the box that allows a specific powder run (it's the left box of the two powder calcs)
The run should be pretty much right at what you're seeing.
That's a pretty basic way to match up QL to your load. You can get significantly more detailed with it but this ways works.
Hope that helps you.

 

[dewey7271]

By the way, changing the Ba is not permanent. Merely change to another powder and it'll reset to default. Just don't save the input changes in QL.

 

[Ned Ludd]

The amount of freebore with which a rifle's chamber is cut largely dictates seating depth, that is, how far down in the neck a given bullet shank will be seated for a specific relationship of the bullet ogive to the lands. This, in turn, dictates "usable" case volume. As has been noted by others, usable case volume is a number that the QL preset values can only approximate for a given cartridge because seating depth is a user input and case thickness varies between different brands of brass. Add to this the fact that powder burn rates can vary quite a bit between different Lots of powder.

Collectively, the preset values in Quickload can give you a reasonable starting point for load development, but you always want to input your load-specific values (COAL, bullet length, barrel length, fired case volume, etc., as soon as you have them. If loading virgin brass, you may not have a good case volume to start and therefore need to use the QL preset value. However, once you've fired a few rounds you can measure case volume and change the input. In general, relative case volumes for for fireformed and re-sized brass will be about halfway in between virgin brass and fired, but not re-sized brass, because we typically only push the shoulder back a couple thousandths during re-sizing. This doesn't matter much as far as the program is concerned because the correct input for case volume is the internal volume of fired brass, which has been formed to the inside of the chamber (i.e. - the pressure cell). However, you will gain a bit more room for powder in fireformed brass so that the fill level may not be quite as "full" for a given charge weight as it is in virgin brass.

Running highly compressed loads is usually not such a good idea to start out. With QL, the easiest approach is to find the predicted MAX safe operating pressure, using whatever preset and/or rifle-specific inputs you have available. You can then back the associated charge weight off by 2 - 5% as a safety margin. Load up some rounds and determine actual muzzle velocity. Then you can go back into QL and "calibrate" the load file for your specific setup by adjusting the burn rate (Ba) as has been suggested. Once you've done that, the predictions will be much better. You may still have to adjust or tweak things as you adjust the load because the relation between charge weight, pressure, and velocity aren't perfectly linear. However, the program will likely give you much better estimates after calibration.

The last point I would make is that reloading manuals are typically set up using mag-length loads and they tend to be pretty conservative. If your COAL is longer than mag length or other parameters vary, the book values may not be representative of what you actually observe. However, they are always a good starting point for safety reasons because you are less likely to accidentally load up a ridiculously hot load straight out of the gate. The best approach is to always start low and work up in small increments. QL is a useful tool that can facilitate and expedite this process, but it is not a replacement for the actual testing process.

 

[Coolhand]

Thanks again Gents , I will be sure to pass on this info , much appreciated .

regards
Mike.

 

[jlow]

There is a lot of good information that has been given, some more related to tuning QL. But for the purpose of evaluating pressure, assuming your bullet, powder remains unchanged, the only two user input factor which affect pressure is case COAL and case volume.