Calibrating (“Truing”) QuickLOAD

[Krogen]

Ah yes, case capacity.

How much water is enough? I agree that QuickLOAD's information is seemingly contradictory:
(i) The data input sheet specifies "Maximum Case Capacity. overflow" and the information box that opens up supports this by specifying "at case mouth overflow", but
(ii) On page 62 of the User Manual it is stated the capacity is based on "water even to end of case neck".

I tried to get to the bottom of this a while ago and, like Alice and the rabbit hole, ended up falling down into a deep dark rabbit hole into a strange and nonsensical world. In the end I took a pragmatic "split the difference" approach. My approach?
(i) First off, how much overflow? That last drop of water, depending on how much water was already in the case, could just fill the case so any overflow was microscopic, or that last drop could end up giving me a nice round convex water drop on top of the case. So,
(ii) I cut the water's surface tension, and hence it's ability to form a drop on top of the case, by adding a very small drop of dishwashing detergent to a cup of water. The with my eye dropper, just touch the water in the case with tiny drops of water at the case mouth until the water is just barely over the top.

As an added bonus, a little to much of this water/soap concoction will quickly result in the water easily running down the outside of the case if you try to add just a little too much water. Hence, it's a convenient check on my technique.

I do this twenty times and average the results:
View attachment 1621144

By the way, I tried using rubbing alcohol instead of water because several people suggested that (it's got less air dissolved in it and a much lower surface tension). Sadly, the standard deviations for the same cases got a lot larger, so I went back to my water & drop of soap method.

I also tried using primer plugs in clean cases instead of fired cases with fired primers in them. Just like my rubbing alcohol experiment, I ended up with worse results for the same cases.

Great post, 222Jim! Thank you. I appreciate your contributions in this thread. Much food for thought.

 

[222Jim]

Great post, 222Jim! Thank you. I appreciate your contributions in this thread. Much food for thought.

Thanks. I appreciate the feedback.

 

[TackDriv3r]

I've attached to this reply the original more details article I posted here. But, In summary:

1. First, I load 10 - 20 rounds with long jump, i.e. 0.080" - 0.100". Then with the shot start pressure @ 3,625 psi, I adjust the Burn Rate rate to get the predicted QuickLOAD velocities to agree with my measured velocities.
2. Second, I load 10 - 20 rounds at shorter jumps, i.e., 10 - 20 at 0.040", another 10 - 20 at 0.020", and then another 10 - 20 at 0.010", etc. Leaving the Burn Rate at whatever I got in the first step, I now adjust the Shot Start Pressure to get the predicted QuickLOAD velocities to agree with my measured velocities.

I use Excel to plot the data; that's the graph shown in the bottom right-hand corner of the third page of the attachment. Now, I simply look up on it the shot start pressure I need to use. For example, if I'm using 0.020" of jump in my .308, I'd use the Burn Rate that worked in the first step, and a Shot Start Pressure of 7,500 psi.

Eyeballing graphs is sometimes a nuisance, so I have a short cut..........Excel gives me the equation too:
Shot Start Pressure = 8,806 - (66,223 x Jump).
That's 7,482 psi.

This two-step approach works for 168 Sierra MatchKings and Varget in my .308, and for Berger 52 Flat Based Varmint bullets in my .222with IMR4198 and .22-250 with Varget. I still need to test it with other powders and bullet combinations.

Any other questions?

That is a learning experience, good stuff. Thanks

 

[InquisA]

@222Jim

So I fell into your work after working with Quickload for the longest damn time and not seeing the results except closely around wherever the published load data is at. You load up most random loads from Hornady or Berger into Quickload and don't modify seating depth or anything like that, and you're almost right on the money. What's a little frustrating is when you do modify those things, Quickload can be significantly off. I've played the CV/CP game as well and that's just a 5 hour trip into hell and aggravation because it's not modeling something that is likely to change much and it will throw you way off if you're working a ladder test.

Quick Rant: As a modeler of thermodynamics and transient, time-based chemical plants, this tells me some things are approximated as opposed to modeled from first principles. Yes, PDE's are hard, but we have the ability to solve those this day in age (ask me how I know). So, for those (not you Jim) that say we are forcing a program instead of letting it lead you, I categorically reject that notion in some instances. Programs need to be modified in cases where they are lacking. If you read the "README.TXT" file inside of the Quickload updates, they tell you there are things they approximate because of lack of measurement capability at their firm, particularly around pressures. Additionally, adjusting parameters to accommodate real world effects is what you are supposed to do. Anyway.

I had a question for you in particular @222Jim : I am shooting VLD bullets in .308 caliber and noticed much lower adjustment factors for Shot Start Pressure (SSP = -14640*[jump in thou] + 6191). Works out to about 15 psig differential per thou of jump. Are you seeing the same?

 

[222Jim]

@222Jim

So I fell into your work after working with Quickload for the longest damn time and not seeing the results except closely around wherever the published load data is at. You load up most random loads from Hornady or Berger into Quickload and don't modify seating depth or anything like that, and you're almost right on the money. What's a little frustrating is when you do modify those things, Quickload can be significantly off. I've played the CV/CP game as well and that's just a 5 hour trip into hell and aggravation because it's not modeling something that is likely to change much and it will throw you way off if you're working a ladder test.

Quick Rant: As a modeler of thermodynamics and transient, time-based chemical plants, this tells me some things are approximated as opposed to modeled from first principles. Yes, PDE's are hard, but we have the ability to solve those this day in age (ask me how I know). So, for those (not you Jim) that say we are forcing a program instead of letting it lead you, I categorically reject that notion in some instances. Programs need to be modified in cases where they are lacking. If you read the "README.TXT" file inside of the Quickload updates, they tell you there are things they approximate because of lack of measurement capability at their firm, particularly around pressures. Additionally, adjusting parameters to accommodate real world effects is what you are supposed to do. Anyway.

I had a question for you in particular @222Jim : I am shooting VLD bullets in .308 caliber and noticed much lower adjustment factors for Shot Start Pressure (SSP = -14640*[jump in thou] + 6191). Works out to about 15 psig differential per thou of jump. Are you seeing the same?

To @InquisA (and others who may be interested).

First off, I spent much of my early chemical engineering career doing modeling as well. Mostly fluid bed reactors and three-phase flow (yes.........solid, liquid and gas) through drying systems. So I can appreciate where your rant comes from!

QuickLoad does indeed make some assumptions, i.e., burn rate curves. But I'm finding I can get results close to forecast with my approach to truing. For example, and by pure and very timely coincidence, I did a jump test yesterday (talk about timing!) substituting Barger 168 VLD bullets for the Sierra 168 MatchKings I usually shoot. Prior to going out, I ran QuickLoad using my trued Ba for Varget and the Shot Start Initiation profile I had worked up using those Sierra MatchKings. Predicted velocities were 2,450 fps and actual were 2,443 fps. I trued Quickload using the velocities I measured yesterday using my approach and found that (i) I had to lower the Ba by 2.5% relative to what I had for those Sierra bullets, and (ii) the Shot Start Initiation pressure profile was only ~9psi/0.001" lower, i.e. Sierra averages 69 psi/0.001" and Berger averages 60 psi/0.001". That's pretty consistent from a jump of 0.080" to just jammed into the lands. Footnote, when I jam .22 bullets in my .222 Remington or my .22-250, I get a noticeable pressure/velocity "bump".

Your 15 psi/0.001" is a long way off from my 60 - 70 psi/0.001", but (and this is just speculation) that could be due to anything from the different geometries of our rifles' throat/leade, barrel (land/groove diameters) effects, to even different primer choice, etc. I did, as an aside, compare your Shot Start Initiation pressures to mine using the formula you included, and did find my pressures are approximately 3,500 psi lower than mine, hence my thoughts on throat/leade geometry and/or barrel dimensions.

Jim

 

[InquisA]

To @InquisA (and others who may be interested).

First off, I spent much of my early chemical engineering career doing modeling as well. Mostly fluid bed reactors and three-phase flow (yes.........solid, liquid and gas) through drying systems. So I can appreciate where your rant comes from!

QuickLoad does indeed make some assumptions, i.e., burn rate curves. But I'm finding I can get results close to forecast with my approach to truing. For example, and by pure and very timely coincidence, I did a jump test yesterday (talk about timing!) substituting Barger 168 VLD bullets for the Sierra 168 MatchKings I usually shoot. Prior to going out, I ran QuickLoad using my trued Ba for Varget and the Shot Start Initiation profile I had worked up using those Sierra MatchKings. Predicted velocities were 2,450 fps and actual were 2,443 fps. I trued Quickload using the velocities I measured yesterday using my approach and found that (i) I had to lower the Ba by 2.5% relative to what I had for those Sierra bullets, and (ii) the Shot Start Initiation pressure profile was only ~9psi/0.001" lower, i.e. Sierra averages 69 psi/0.001" and Berger averages 60 psi/0.001". That's pretty consistent from a jump of 0.080" to just jammed into the lands. Footnote, when I jam .22 bullets in my .222 Remington or my .22-250, I get a noticeable pressure/velocity "bump".

Your 15 psi/0.001" is a long way off from my 60 - 70 psi/0.001", but (and this is just speculation) that could be due to anything from the different geometries of our rifles' throat/leade, barrel (land/groove diameters) effects, to even different primer choice, etc. I did, as an aside, compare your Shot Start Initiation pressures to mine using the formula you included, and did find my pressures are approximately 3,500 psi lower than mine, hence my thoughts on throat/leade geometry and/or barrel dimensions.

Jim

Complete three phase flow is an absolute monster, you have my admiration. Most of my models were liquid-liquid or liquid-gas tray interactions for distillation tray geometries, radiant heating of fired furnaces with liquid feed, and suspended catalyst bed oxychlorination reactions. Nowadays its all about convincing junior engineers that what they learned in school works, they have to learn to apply it right.

I've been having a particular bit of consternation with Accurate 2460 in .308 Winchester. I have attempted modeling it against a an AR-10 .308 with some chrono data and have not had any success in finding any way to mimic what I see on the chrono inside of QuickLoad. Varget is a bit aggravating to model in there too, though I am measuring against published load data and then changing to my barrel length, as opposed to chrono data. I am working on finding if OBT nodes work in that barrel, so I need to a) shoot a ladder test and b) tune QuickLoad to that.

Back to the cartridge (300 PRC) I am working up with your method: I re-ran what I think your method is and it came up saying I the shot pressure on this cartridge is the same as the shot pressure on the spec cartridge, so now I'm completely lost.

 

[Jason D Hostetter]

Don't forget to calculate your overbore index, default isn't always correct, in fact more often than not, it's wrong. It's the little box at the bottom right of the left portion of the screen. Usually ranges from .45-.6, tweaking that number can allow you to have velocities line up with chronograph data, in more than one or possibly two charge weights, but allows it to line up across the entire range of charge weights across a given powder. You can get your input, by measuring actual case h2o capacity.

 

[InquisA]

Don't forget to calculate your overbore index, default isn't always correct, in fact more often than not, it's wrong. It's the little box at the bottom right of the left portion of the screen. Usually ranges from .45-.6, tweaking that number can allow you to have velocities line up with chronograph data, in more than one or possibly two charge weights, but allows it to line up across the entire range of charge weights across a given powder. You can get your input, by measuring actual case h2o capacity.

I ran the numbers, based on a anecdotal formula someone developed a while ago, something like

x = 500/ overbore index.

For my .308, it came out as .667. Sound reasonable? Or am I off in the dark here?

 

[222Jim]

Don't forget to calculate your overbore index, default isn't always correct, in fact more often than not, it's wrong. It's the little box at the bottom right of the left portion of the screen. Usually ranges from .45-.6, tweaking that number can allow you to have velocities line up with chronograph data, in more than one or possibly two charge weights, but allows it to line up across the entire range of charge weights across a given powder. You can get your input, by measuring actual case h2o capacity.

You can find approximate Overbore Indices here:

https://bulletin.accurateshooter.com/2014/03/overbore-cartridges-a-working-definition/

For QuickLoad, the Weight Factor is 500/Overbore Index.

I actually measure my case volumes (average of 20 cases with spent primer in them) and prorate their Case Volume to Bore Area up/down, as applicable. It makes a slight difference, and the main reason I do it is because I always use my actual (fired) case capacity instead of the default values.

 

[222Jim]

Complete three phase flow is an absolute monster, you have my admiration. Most of my models were liquid-liquid or liquid-gas tray interactions for distillation tray geometries, radiant heating of fired furnaces with liquid feed, and suspended catalyst bed oxychlorination reactions. Nowadays its all about convincing junior engineers that what they learned in school works, they have to learn to apply it right.

I've been having a particular bit of consternation with Accurate 2460 in .308 Winchester. I have attempted modeling it against a an AR-10 .308 with some chrono data and have not had any success in finding any way to mimic what I see on the chrono inside of QuickLoad. Varget is a bit aggravating to model in there too, though I am measuring against published load data and then changing to my barrel length, as opposed to chrono data. I am working on finding if OBT nodes work in that barrel, so I need to a) shoot a ladder test and b) tune QuickLoad to that.

Back to the cartridge (300 PRC) I am working up with your method: I re-ran what I think your method is and it came up saying I the shot pressure on this cartridge is the same as the shot pressure on the spec cartridge, so now I'm completely lost.

Two comments.

First, I think there's a typo or accidental grammar error in the last paragraph. Can you clarify what you meant?

Second, I had a hell of a time trying to true QuickLoad for my M1A, and wasn't happen with my results when the Government of Canada banned my Springfield Armories M1A is a "weapon of war" with a "buy-back", also known as "confiscation", coming. That was 5 years ago and to date nothing has happened, other than the fact that if I take it out of my gun vault, I go to prison.

Rant over....... QuickLoad was designed, as much as I can tell, for bolt action rifles. From what I've read semi-automatics, and gas operated rifles in particular, apparently aren't handled well. Issues include the gas bled from the barrel to drive the operating rod as well as the carrier action/opening timing mess with what's assumed to be driving the bullet forward.

 

[Jason D Hostetter]

I ran the numbers, based on a anecdotal formula someone developed a while ago, something like

x = 500/ overbore index.

For my .308, it came out as .667. Sound reasonable? Or am I off in the dark here?

I'd say your number is probably pretty close, as a 308 isn't overbore much at all, only a handful of cartridges are less overbore.

 

[Darkside]

WOW
A great thread guy's, I am just starting down this rabbit hole. Thanks

 

[Webster]

I’ve documented my methodology to calibrate (“true”) QuickLOAD that gives me predicted velocities that are typically within +/- 5 fps of my measured velocities.

The foundation of this method is, for a given handload (caliber, powder & charge, and bullet), to enter the obvious factors (i.e., actual bullet weight and diameter, cartridge and case length, barrel length, and maximum case capacity) and an improved estimate of the weighing factor. Then adjust the:

• Powder Burn Factor until the predicted and measured velocities match for large jump handloads, then
• Shot Start (Initiation) Pressure until the predicted and measured velocities match at different jumps.

I’ve tested this on three rifles (.222 Remington, .22-250 Remington, and .308 Winchester) using two different bullets (52 gr Berger Flat Based Varmint and 168 gr Sierra MatchKing) and two different powders (IMR4198 and two different lots of Varget). Adjustments I needed to make to the Burn Rate Factor and Shot Start (Initiation) Pressure to calibrate (“true”) QuickLOAD were within accepted ranges.

If this interests you, my methodology and results are described in more detail in the attached pdf document.

I’d welcome your thoughts, comments, and suggestions on what bullets and powders to apply this to next.

What's the QL definition of a node?

 

[BoydAllen]

Seeing the amount of work it has taken you to "true" Quickload, I do not think that I will bother. It gives me a way to compare powders for the same application, and come up with a safe starting load, which is all that I really need, given that I have a chronograph. I want to thank you for sharing your excellent work. I am sure that there are many who will put your knowledge to excellent use.

 

[222Jim]

What's the QL definition of a node?

I searched for the word "node" in the QuickLoad user's guide. No results.

QuickLoad does report 10% Pmax to muzzle exit, which many take to equate to timing with respect to a node. But I'm not convinced given the vibrations will start upon primer ignition. But it's as good a proxy as I can find. Plus, I've found my best (most precise) loads don't necessarily line up with published node times anyway!