Accuracy of Quickload

[Ben_Snow]

Just purchased 1lb of Vihta N320. Will be used to load 38SP for a S&W 686 and a Ruger GP100 using a 158gr Berrys Plated Round Nose with a 1.47 COL. Both have 4" barrels.

The Vihta website for 38SP using an equivalent Ranier bullet 158gr at the same exact COL indicates the safe tested range at 3.8gr to 4.8gr.

Quickload indicates that even the low end using 4.2gr of N320 is above PMAX. I would tend to favor the Powder manufacturer's data, but why is QL indicating danger for load? Quickload Chart

[Don Fischer]

I don't know what quickload is really, never seen it. I have always used bullet manufacturer's load data. Now that may be off in your gun also. That is why they start low and work up. I'm guessing Berry doesn't have a manual? With that, if the powder manufacturer does, use that manual. Is this Berry plated a cast bullet or what? Know nothing abut them either! Keep in mind that all, ALL, printed data is a guide used in a particular firearm on some certain day with different lot's of powder and bullet's. If you start at the bottom and work up you'll likely now find any data that won't work in your firearm.

[Ben_Snow]

Don:

The question is whether the Quickload software is accurate, it conflicts by a huge margin with data from the powder manufacturer.

Here is info on Quickload if you are unfamiliar with the software: http://www.neconos.com/category/Software-2

To answer your questions:

"Is this Berry plated a cast bullet or what" ....No, its copper plated using a electrolysis process over a swagged lead core

"I'm guessing Berry doesn't have a manual?" .......No, they produce a COL chart, but that is just retreaded data pulled from SAAMI.

[Marco Califo]

Quick load is a predictive model based on burn rates and pressure curves. Berry's are Copper Plated. They also sell plated hollow point hybrids like Gold Dots. Berry's website, while not having, data, does include guidance for adapting load data from other sources.
Find the closest match in V. data.
38Spl is a low pressure cartridge and it sounds like you will be shooting in 357Mag pistols providing a margin of safety.
You can write to QL and V. And ask. But since V. tests their load data, I would trust V. data over QL predictions. QL does not actually test anything, and may have some bad data.
Use Ranier bullet data as is for same weight Berrys.

[74A95]

Ben, use pressure tested data. QL is no substitute for actual test data.

Here is a quote from QuickLOAD, “Based on a theoretical model and not on empirical data from any tests. Ballistic programs such as QuickLOAD cannot predict EXACT internal ballistic results. Therefore one CANNOT use the software as a substitute for information gleaned from a reloading manual along with standard handload development and practices. QuickLOAD is designed and
intended only for use by those persons who are completely familiar will all safe handloading practices. It is mandatory to verify any computer-generated results with data found in current manuals. NEVER use charges exceeding recommended maximum charges or reduce charges below recommended minimum (start) charges as representing in such modern manuals.”

[Unclenick]

Ben, in addition to the above:

What is the length of the Berry's bullet? What is the length of the Ranier bullet? Note that the Ranier 158 in the QL database is the T type, which I don't currently see listed, while the VV data is for a FP design. FP's are usually shorter for weight than anything but a true wadcutter, making the volume under the bullet greater for a given COL than for anything but a wadcutter. Small changes in bullet length can make a big pressure difference in pistol loads because the short powder column doesn't need much difference in bullet base position (governed by seating depth) to make a big percent change in the powder space.

BTW, why are you using the shorter-than-max COL with a RN bullet?

Note the QuickLOAD (QL) powder data are arrived at by measuring the behavior of purchased samples in a vivacity bomb test. If the test was done on a lot that was faster than average, the result can calculate to be a bit high.

Note that QL was developed using CIP standards. VV powders are tested to CIP standards for with .38 Special, for which the peak pressure is 21,756 psi. You want to use that CIP model and not the SAAMI model to make the comparison.

Note that QL's combustion model works best with bottleneck rifle cartridges it was originally developed for. I have noted a few instances in which straight wall cases have needed to have a little bit of false volume added to them to get matching velocity or pressure performance. Read Chris Long's paper on tweaking QL to match actual performance.

Note that QL errs on the conservative side by usually having the default cartridge case volumes at the minimum you are likely to find. Measure yours. For cartridges peaking at pressures below 30,000 psi, and for which the case does not stick to the chamber, it is recommended you use the resized case water overflow capacity in QL. For cartridges over that operating pressure you use the as-fired case water overflow capacity.

Case water overflow capacity is measured by plugging the primer pocket of a case the same length as the QL case (or else change the default length) with clay or leaving a spent primer in it (but you'll have to remove your decapping rod from your sizing die to get a resized case with the spent primer still in place). Then you weigh the case, and record the dry weight number. Then you fill the case with water level to the mouth with no meniscus and no air bubbles and no drops on the outside (takes a little practice). Weight the water-filled case and subtract the dry weight. Enter this into the Maximum Case. overflow window.

Call Ranier and get the length of the bullet you found in the VV data. Find its seating depth (Shank Seat Depth window in QL) by entering the published COL and give your bullet that same seating depth to see what COL you get.

FYI:

Seating Depth = Case Length + Bullet Length - COL

[mehavey]

QuickLoad is absolutely indispensable when
(1) No other data is available that matches powder, bullet, case, primer, barrel length, etc (i.e., "the manuals")
(2) When the shooter has access to a chronograph.
(3) When the shooter realizes that QL has (and clearly states it has) problems w/ straight-wall cartridges
(4) When the shooter looks at what data there is that is published for comparison
(5) When the shooter starts mid/low to get a chronograph reading, and then knows enough to adjust the effective burn rate for that chamber, that barrel, that powder-lot, that primer, that case, that bullet, and that OAL.

[Ben_Snow]

....

[ShootistPRS]

Ben,
I think you actually understand the limitations of internal ballistics software.
You can interpolate information for loading straight wall cases more closely with a pencil and some comparative math.
This is not a recommendation to use interpolated data in your reloads without checking them against know valid data. (of course if you had known valid data why would you need to interpolate data?

Catch 22

[Ben_Snow]

...

[disseminator]

I have found quickload to be about as accurate as the data you put into it.

It has been invaluable in working up loads with the ability to try many different powder and bullet combinations without having to buy a bunch of powders and bullets I may not like.

This alone has paid for the program a few times over at least for me.

As far as accuracy with straight wall, I'd say YMMV. I couldn't find any load data for 230 grain WFNGC bullets for the 10mm so I took some careful measurements and added that data to QL and it came up with a max load that I then reduced and worked up to that was within a few dozen FPS.

That's pretty sweet.

[Stats Shooter]

Quickload is a great tool.... especially when you are way off book with custom chambers, barrel lengths, and using bullets for which there is no data.

Quickload is only as accurate as the data you put into it. There are some default settings that might not apply to what you are doing.

With the cartridges I have modeled extensively, Quickload is within 25 fps but that requires a lot of case/chamber measurement, bullet measurement, etc.

But, it does have limitations and as mentioned, it has issues with straight walled pistol cases.

Many folks on here are probably familiar with math modeling. In my line of work we use them extensively. But, we begin with a general model, and then use observed data to tailor the model to a specific circumstance or situation.

I do the same with Quickload adjusting some settings until my observed velocity supported by 2 know to be accurate chronographs is identical and then I can reasonably expect that the model will predict actual outcomes.

I will also note that reloading manuals and resources often disagree. If you have time, try looking at the powder companies data, then the bullet makers data for the same powder, the Lymans more general manual. They all 3 can and often do have different Max's, mins, and velocities even with the same primer and barrel length (i.e the 175 gr match king in .308 with imr 4064, Sierra's max is Hodgdon's suggested starting load and Lyman is in between)

[tangolima]

Originally Posted by ShootistPRS

This is not a recommendation to use interpolated data in your reloads without checking them against know valid data. (of course if you had known valid data why would you need to interpolate data?

You mean extrapolation not ok? Interpolation should be fine, but extrapolation is dangerous. For example if I get from test firing

3.0gr, 1000fps
3.5gr, 1500fps

Then 3.25gr should be safe and the speed should somewhere between 1000 and 1500fps, probably 1250fps.

However it would be dangerous to assume 4.0gr safe for 2000fps.

I myself do interpolations all the time, both in my day job and handloading. But I only do extrapolation when I absolutely have to, and with small deviation. Taking the above example, if there are no signs of over pressure at 3.5gr, perhaps step the charge up to 3.6gr.

-TL


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[Unclenick]

I've seen a number of members interchange the two terms. The thing to remember is the prefix "inter" means inside, as in between the start and maximum load. The prefix "extra" means outside. So to interpolate is to pick out the trend between two established data points, and to extrapolate is to try to see where the trend is going outside that range.

What makes extrapolation dangerous is that while a straight line fit of powder charge between start and maximum (and even outside the range for a short distance) will predict velocity pretty accurately, velocity is not proportional to average pressure in the gun. That is because, as the bullet speeds up the barrel time gets shorter. So, even if you double pressure and therefore the force at the base of the bullet, that higher pressure doesn't have as much time to accelerate the bullet. The result is the bullet velocity only goes up as the square root of the average pressure difference. In other words, average pressure predicts muzzle energy but not muzzle velocity. So average pressure is going up as the square of velocity.

But we don't concern ourselves with average pressure, we concern ourselves with peak pressure. That goes up even faster with powder charge than average pressure does. Hence the hazard and the general warning in your chronograph instructions not to use velocity to try to determine pressure indirectly.

[redford1]

Read Chris Long's paper on tweaking QL to match actual performance.

Is there anywhere that this quickload help files are posted

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[disseminator]

QuickLoad is a computer program written by people who very likely have never seen a real firearm. There are far too many variables for any computer program to be accurate.
However, Vihtavuori's data is done to CIP specs, not SAAMI. QuickLoad doesn't count at all.
"...bullets for which there is no data..." You do not require bullet specific data. The only thing hat matters is cast or jacketed and the weight. And 'close' counts for the weight. 5 grains either way won't matter.

Even if your statement that QL was written by people who haven't seen a real firearm were true, which it is most definitely not, it would make little difference as ballistics is totally Mathematical and can be predicted with GREAT accuracy given accurate input.

Just yesterday I was thinking, people are really hard on that T. O'Heir and maybe he doesn't deserve that, but then you posted this nonsense and I remembered why. There are a great many things most of us know, but a lot more that we do not. The mark of maturity is being able to know the difference and learn when an opportunity arises.

As for Vihta using CIP data, QL has both CIP and SAAMI for many cartridges and if you knew anything about QL you would know that. I use VV powders in a bunch of different pistol and rifle calibers and QL has been very good about predicting velocities with all of them.

I have no vested interest in QL, but your repeated statements against it are just silly and un-informed.

[buck460XVR]

This is the best advice I've seen for the use of QuickLOAD, from Wikipedia.

QuickLOAD mainly helps reloaders understand how changing variables can affect barrel harmonics, pressures and muzzle velocities. It can predict the effect of changes in ambient temperature, bullet seating depth, and barrel length. However, QuickLOAD has limitations. It is merely a computer simulation. It doesn't account for different brands of primers for example, and its ability to predict the effect of seating bullets into the rifling is crude. A QuickLOAD user most certainly should not just "plug in" a cartridge, bullet and powder and use that load, assuming it is safe. It is good practice to double- or triple-check QuickLOAD's output against reliable load data supplied by the powder producing companies. Of course the best way to check firearms cartridge loads are actual proof test measurements at certified test facilities.

Love it or hate it, QuickLOAD is just another tool in a reloader's arsenal. As such, it is also subject to opinions, both positive and negative, as any other tool. Folks, regardless of positive or negative opinion, are entitled to their opinion. Printed recipes as well as QuickLOAD can be "interpolated" or "extrapolated" correctly/incorrectly and safely/dangerously.

[tangolima]

Originally Posted by Unclenick

we don't concern ourselves with average pressure, we concern ourselves with peak pressure. That goes up even faster with powder charge than average pressure does. Hence the hazard and the general warning in your chronograph instructions not to use velocity to try to determine pressure indirectly.

By analyzing a bunch of published data, I established a few empirical equations that help me be safe when I need to extrapolate. One of them is relationship between muzzle velocity and peak pressure. I keep those equations to myself because of the risk associated with the practice.

QL is a another (better though) such tool as those equations. I will buy it one of these days.

-TL



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[higgite]

Originally Posted by Unclenick

Read Chris Long's paper on tweaking QL to match actual performance.

Nick,

Someone, probably you, posted that link a while back. After reading it, I managed to tweak QL to match my chrono readings to within 10 fps for 12 different 9mm Luger test loads involving 3 different bullets. I experienced similar accuracy for a number of .45 ACP test loads. I don't take it as gospel, but do find it handy for doing 'reasonable' what-ifs. For instance, after testing 3 incremental test loads and getting chrono readings lower than I wanted, I used QL to predict the powder charge for my target MV. I worked my way up to that load and the average MV was within 10 fps of my target, so I called it good.

My only concern at this point is that I can manipulate powder Ba, bullet weight and case capacity in various combinations to get the same MV readout for the same charge weight, but pressures are different for different combos. Any thoughts about that?

[Unclenick]

Redford1,

I think your own link is an example. The manual can probably be downloaded with the free demo from NECO. Otherwise you need to ask specific questions of more experienced users to get answers.


What QuickLOAD does best is get you relative change information when you change a parameter, like seating depth or powder burn rate. If it says the pressure changed 5%, then, even though the absolute pressure is different, the 5% change is very close. Occasionally it is right on actual measured numbers, but more frequently it is off by some percentage compared to published data. This is often due to component and powder lot differences more than anything else. I've seen .223 data for which a change from mild to magnum primer raised velocity 5% and peak pressure probably almost 12%.

Extrapolation can, to a degree, be checked in QL by percent change if you first get a good match to published pressures.

At the last NRA Annual Meeting, I spent some time talking to Dr. Ken Oehler, who has been in the commercial ballistics equipment business for a long time. His opinion was that pressure measuring was difficult to have high confidence with beyond about 5% of absolute, so you have that sort of reality allowance to make even to what is published as a measurement. If you look at this Somchem data, you can see velocity changing almost 2% (60 fps out of 3,000 fps) just with powder lot variation. Average pressure, as I said, varies as the square of velocity, so that would be about a 4% variation in average pressure and probably closer to 5% in peak pressure. Even the best government super computer running the most sophisticated and detailed models could not, therefore, be counted on to make a prediction any more precise than that without having been adjusted to match the particular powder lot you are using and ll the other components.

The bottom line is that when powder variation and measuring limitations are taken into account, it's pretty likely that reality varies by 10% from the ideal with some frequency and maybe a bit more when individual gun differences are taken into account. SAAMI allows individual round pressure measurements to vary by over 18% in the extreme. The CIP limits it to 15%, but you can get the idea from both those numbers that variation from the ideal at these percentages are not out of the question and so you can't expect any prediction to do better than that in all instances.

Bottom line, QuickLOAD will usually give you real velocity within 5% but occasionally can only get within 10% for some combination. Corresponding pressures would be within about 12% and worst case 25% in error, though I don't see something like that very often. I know it sounds large, but 25% is actually not too far off from what reducing charge weight 10% does for some powders. But check the real data for confirmation. With some chronograph feedback you can narrow it considerably. Once you have it narrowed for a lot of powder and gun you own, you can predict things much more closely.

[redford1]

Thank you Unclenick
I have quickload just need to learn to make it match my chrono readings. Like everyone says its not so good with straight wall cases.

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