Calibrating (“Truing”) QuickLOAD

[222Jim]

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.

 

[Steveb]

I am the same as yourself as I really like using the software to predict nodes and for the most part it really seems to work. However , the biggest issue I have is determining the Stop Start Pressure. I use match loads that use jammed bullets or small jumps. I start normally with a heavy jam and back the bullets up. At some point you move from jam to jump and at that point the Initiation pressure changes. I know you are supposed to reduce the initiation pressure per .001" reduction in jam but it doesn't seem to make enough of a change. I find either jam or massive jump seem to give the best results but I would like more information about loads with .010" to .030 jump.

 

[222Jim]

If you haven't, take a look at the more details in document I attached to the original post.

I adjust the Burn Rate Factor using handloads that jump of 0.100" - 0.080" range, then once I've got the Burn Rate Factor set, I adjust the Shot Start Pressure to match predicted to measured velocities at lower and lower jump. Interesting that in my .222 and .22-250, the Shot Start Pressure increases by roughly 33 psi/0.001" of reduced jump. With my .308, it's more like 69 psi/0.001", but as I get closer to jam, that value appears to start increasing. It's not statistically valid though. So I do want to do tests from 0.005" jump, 0.005" jam and 0.010" jam, then 0.030" of "soft jam", to see if the Shot Start Pressure does increase faster.

Note that I personally avoid the 0.005" jump to 0.005" jam range because I know that unless I lubricate the bullet and inside of the case neck (NeoLube No. 2), on a bad day my seating is +/- 0.005" (2 standard deviations for 20 handloads). Consequently, I make jump moves in at least 0.005" increments, and at less than 0.005" of jump, I'm not convinced I can guarantee to myself a bullet that should jump isn't actually jammed. Of course, if I lubricate, that "on a bad day" jump error is reduced to less than +/- 0.003". Better, but that doesn't justify trying 0.000" jump.

FYI, lubricating does reduce seating depth variation, but I haven't yet seen any impact on velocities or shooting precision when I do or don't lubricate, but I'm still working on that!

 

[Steveb]

Good comments but I believe you are assuming that the Burning Rate doesn't change as the pressures increase due to increasing jam pressure. We do know that this does happen so I do question your assumption in this and possibly using a false premise to adjust your initiation pressures.

I also agree there is no point in trying for accurate loads in the .005" jump to jam range. I have also found inconsistent accuracy results.

Great thread through.

 

[Jager]

I, too, am a happy user of QuickLoad. I'll just point out that tweaking Shot Start Initiation can be a challenge simply because most of us don't have an extremely precise measure of exactly how much the bullet is into the lands... there being a pretty extended range of "touch" between clear jump and hard jam.

There's also an inflection point where touch first begins... where the inevitable bullet-to-bullet sample variation (when measuring to thousandths) means that some bullets are just starting to touch while others are still jumping.

But those challenges notwithstanding, Shot Start Initiation is probably an area deserving of more attention. Best of luck in your research!

Two other quick thoughts. QuickLoad is a linear model whereas increasing charge levels will exhibit (real) chamber pressure increases more on a curve. I typically true QL at the highest-pressure end of a ladder, since that's what I'm usually most interested in.

The most important external factor that I think gets too little attention with respect to truing QL (and actual velocities, as well) is powder temperature.

 

[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.

Sounds like your forcing the program to give you results you like. Adjusting burn rates and pressure numbers so you match chrono numbers. A computer program cannot tell you what will shoot small in your rifle. I quit using my chrono, I just shoot till I see small round groups. Both my rifles easily shoot under 1/2" with any load.

 

[222Jim]

I, too, am a happy user of QuickLoad. I'll just point out that tweaking Shot Start Initiation can be a challenge simply because most of us don't have an extremely precise measure of exactly how much the bullet is into the lands... there being a pretty extended range of "touch" between clear jump and hard jam.

There's also an inflection point where touch first begins... where the inevitable bullet-to-bullet sample variation (when measuring to thousandths) means that some bullets are just starting to touch while others are still jumping.

But those challenges notwithstanding, Shot Start Initiation is probably an area deserving of more attention. Best of luck in your research!

Two other quick thoughts. QuickLoad is a linear model whereas increasing charge levels will exhibit (real) chamber pressure increases more on a curve. I typically true QL at the highest-pressure end of a ladder, since that's what I'm usually most interested in.

The most important external factor that I think gets too little attention with respect to truing QL (and actual velocities, as well) is powder temperature.

Propellent temperature is something most folks don't touch, although I agree more people should understand it (and when to leave it alone for temperature insensitive powders).

Up here where I live it ranges from between 85F (30C) to -22F (-30C). But, I'm a fare weather shooter, so most of my shooting is done within a narrower 50F (10C) to 75F (25C) range. But occasionally I do adjust the powder temperature in QuickLOAD to see how my predicted velocities change. BUT, going forward, I'll pay more attention to that. Thanks for the reminder.

 

[222Jim]

Good comments but I believe you are assuming that the Burning Rate doesn't change as the pressures increase due to increasing jam pressure. We do know that this does happen so I do question your assumption in this and possibly using a false premise to adjust your initiation pressures.

I also agree there is no point in trying for accurate loads in the .005" jump to jam range. I have also found inconsistent accuracy results.

Great thread through.

I agree that the burn rate is likely affected (effected?) by chamber pressure. I just don't (yet?) know how to manage that. Another issue that isn't well understood is the transition between progressive and degressive burn rate (i.e. left vs. right of that vertical "Z1" line). I've read that achieving peak pressure at the Z1 point improves precision, but I've yet had time to prove that true or false.

 

[222Jim]

Sounds like your forcing the program to give you results you like. Adjusting burn rates and pressure numbers so you match chrono numbers. A computer program cannot tell you what will shoot small in your rifle. I quit using my chrono, I just shoot till I see small round groups. Both my rifles easily shoot under 1/2" with any load.

Trying to get the model to agree better with reality - if the velocity matches reality, maybe barrel time (10% PMax to muzzle), etc. will be better too.

 

[Steveb]

Hi Jim I live in the interior of BC where the temps range same as Calgary and we shoot competition from as low as we can stand (-25C to -30C) to as hot as we can also stand +45C so my charges and powder types must handle the temp swings. I tend to load to the middle nodes of about 60,000 psi - 62,000 psi ranges. Some powders I have noticed work well at the lower temps while some work better at the higher temps so adjusting variables can get a little tricky at times.

I do know that when things "line" up correctly QL can get very close in the predictions. Last Sunday I tried a load that was estimated from prior data and burn rate adjustments to have a predicted velocity of 2652 fps and the tested average actual was 2649 fps. Close enough for me!!

Another variable that there is no adjustment for is the type or make of primers. I weigh my match load primers and it is amazing the difference in velocity that simply using high weight primers verses low rate primers can bring.

 

[222Jim]

Hi Jim I live in the interior of BC where the temps range same as Calgary and we shoot competition from as low as we can stand (-25C to -30C) to as hot as we can also stand +45C so my charges and powder types must handle the temp swings. I tend to load to the middle nodes of about 60,000 psi - 62,000 psi ranges. Some powders I have noticed work well at the lower temps while some work better at the higher temps so adjusting variables can get a little tricky at times.

I do know that when things "line" up correctly QL can get very close in the predictions. Last Sunday I tried a load that was estimated from prior data and burn rate adjustments to have a predicted velocity of 2652 fps and the tested average actual was 2649 fps. Close enough for me!!

Another variable that there is no adjustment for is the type or make of primers. I weigh my match load primers and it is amazing the difference in velocity that simply using high weight primers verses low rate primers can bring.

Curious what caliber you shoot. I weighed primers (hell, after I bought my A&D 120i and I weighed everything from cat whiskers to primers), and even found some primers with very large weigh differences. But when I tested them in my .222 and .22-250, I saw no difference. Having said that, I do see large precision difference between primer brands.

 

[Steveb]

I weigh my primers for major long range F-Class matches in my 284 using 180 grain bullets. I don't bother for the closer range matches or my 6.5 Creedmoor's using SRP's.

 

[Krogen]

222Jim, I'm interested in your comments about case water capacity and how it's properly measured for use in Quickload. Quickload documentation and the user interface are contradictory. There are directives to fill the case to overflow while elsewhere it states "level."

I experimented with a .223 Remington using 80.5 gr Bergers. They are seated long; the barrel has a 0.169" freebore. This allows greater powder charges without excessive pressure. Initially, Quickload predicted extreme pressures (which of course I couldn't verify) and much higher velocities compared to my Garmin. Measuring water capacity to the brink of overflow and modifying that variable in Quickload brought the predicted and measured velocities in line with each other.

My results and the fact that Quickload's stated methods are contradictory make me suspicious that other cartridges may also have incorrect water capacity in the database. What are your thoughts on this?

 

[222Jim]

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:


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.

 

[Webster]

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.

Is there really such a thing as case volume? The powder burns in the space behind the bullet as it moves forward. This amounts to the same thing as the case volume constantly increasing. Alcohol may fill the primer cup better thru the tiny hole. I don't remeber which brand primer it was but on 1 popular primer I could see different amounts of the primer charge ozzing up around the paper disc and anvil. Most primers you cannot see the primer charge? Don't know if the wt. of the charge varied or if the paper disc was pushed down a little more causing the charge to be exposed. One brand of primers has all the anvils stained the others are bright and shiny.

 

[TackDriv3r]

Interesting, on Quickload, the shot start ( initiation ) pressure for jacketed rifle bullets is 3625 psi, do I leave it as is for .005" to .020" off the lands? Do I change it and how much? Do you change this shot start each time you calibrate on QL ? I always have adjusted the burn rate and temp only to match my chrono speed. I am curious.

 

[222Jim]

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?

 

[Steveb]

I really like QuickLoad as an engineering type myself and find it very useful. However it can get a little interesting if you don't get the variables right and that is why I am interested so much in the Initiation pressures. I like what you are doing Jim. Makes sense to me.

Today i went to test some loads I use for a rifle I use only for 300 Meter F-Class. I set the parameters with the following.
Temp set to 75 F
Burning rate from previous 146 grain loads at .482
Initiation Pressure 3626 because I set the OAL length for magazine feeding with lots of jump.
Barrel Length 26"
Results show a load at 44.9 N160 2819 fps 59602 psi Barrel Timing 1.262 for Node 4 1/2

I shot it this morning and got extractor marks on the brass so I knew I was high and my velocity was also more than I thought at 2904 so I quit after a 2 rounds.

I came home and redid the parameters to the following

Temp at the time was 36 F
Burning rate revision indicated a burning rate needed to be .515 for this bullet weight and temp
Same Initiation Pressure and barrel length.
New results show the load now is 43.5 N160 2819 fps 60182 psi Barreling timing 1.26 for Node 4 1/2

This charge is more like it and I will test Sunday again.

This though does show the importance of getting all the variables set right. Here I had the wrong temp and burning rates wrong for the bullet weight and ended up with an over pressure load. With this burning rate the 44.9 charge now indicates an 68,000 psi load which explains the extractor marks.

 

[222Jim]

Getting all the variable rights............getting them wrong can be a big problem. I use a check list for everything I change. Last step before moving over to the reloading bench is to double check what I entered in QuickLOAD is what's on my checklist.

 

[Big_Daddy]

222Jim, I'm interested in your comments about case water capacity and how it's properly measured for use in Quickload. Quickload documentation and the user interface are contradictory. There are directives to fill the case to overflow while elsewhere it states "level."

I experimented with a .223 Remington using 80.5 gr Bergers. They are seated long; the barrel has a 0.169" freebore. This allows greater powder charges without excessive pressure. Initially, Quickload predicted extreme pressures (which of course I couldn't verify) and much higher velocities compared to my Garmin. Measuring water capacity to the brink of overflow and modifying that variable in Quickload brought the predicted and measured velocities in line with each other.

My results and the fact that Quickload's stated methods are contradictory make me suspicious that other cartridges may also have incorrect water capacity in the database. What are your thoughts on this?

I am lucky enough to get to shoot both guns and the "bull" with Krogen on a very regular basis.
I too was showing over pressure situations with my 223 Prairie Dog loads that I have used for years.

Krogen keyed my into measuring grains of water and once corrected in QL, the predicted pressures came in line.

So far, the 223 is the only caliber that I have had this issue with.

You can learn something new everyday.....if you are willing to listen...