A question for you reloaders using QuickLoad. I am familiar with the process of measuring my cases for water grains capacity. QuickLoad recommends using fired cases, if over 30,000 psi, for proper case capacity when using the program. That is if I am understanding what I am reading and is what I see in other threads. My question is I always full length size my fired cases and bump the shoulder back .0015 before loading. My rifles are for both hunting and range shooting. What is the proper measurement I should be using?
Clarification needed for QuickLoad case capacity measurement
- Thread starter amtx2019
- Start date
Jager
Gold $$ Contributor
Size/prep your brass however you normally do. Measure the volume of a sample set of that brass - before it is sized - average those numbers, and use that average in QL.
If I am loading new, virgin brass I will measure the volume of that brass, just as it is. But once it is fired, its volume will change... so measuring again is called for.
If I am loading new, virgin brass I will measure the volume of that brass, just as it is. But once it is fired, its volume will change... so measuring again is called for.
I measure as I would use it. Fire formed case if I am not FL sizing. FL sized case if I am FL sizing. Using an average, as mentioned, IMO is important as is using fired brass. TBH. I really only use QL during load development. Once I get to the point where I have to bump the shoulder or FL size my fire formed cases, I pretty much already know what my charge weight is going to be. I think adjusting the burn factor to match your measured velocities is also important.
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Ned Ludd
Silver $$ Contributor
Use the water volume of a fired case...exactly as the QL instructions state. Do not re-size or process the brass in any other way, except for turning the primer around backward in the pocket, which makes for a better volume measurement. You want to use the volume of the "pressure cell", which corresponds to the internal volume of a fully expanded case in the chamber at peak pressure during firing. That is the true pressure cell volume. That is the volume in which the combustion process is initiated and is what the program wants as an input. Of course, the brass case does contract a very small amount as soon as the pressure reduces, which fortunately makes it easier to extract, but the relative effect of this is small enough that we ignore it when inputting case volume into a QL file because there is no good way for most people to ever measure the true pressure cell volume.
It takes relatively little energy to expand a re-sized/processed case back to the maximum pressure cell volume during the firing process, because we not reducing the external dimensions of fired brass all that much during the re-sizing process. In my hands, re-sized/fully process brass typically has a case volume very close to halfway in between that of virgin brass and fired brass. The volume differences between the three states depend on the the inherent internal volume for a given cartridge and the chamber specs in which it was fired, but can be as much as several grains. The bottom line is that if you use as an input the volume of a piece of virgin brass, or fired brass that has been re-sized and fully processed, you are inputting a value substantially lower than the true pressure cell volume and it will distort the outputs proportionally.
It takes relatively little energy to expand a re-sized/processed case back to the maximum pressure cell volume during the firing process, because we not reducing the external dimensions of fired brass all that much during the re-sizing process. In my hands, re-sized/fully process brass typically has a case volume very close to halfway in between that of virgin brass and fired brass. The volume differences between the three states depend on the the inherent internal volume for a given cartridge and the chamber specs in which it was fired, but can be as much as several grains. The bottom line is that if you use as an input the volume of a piece of virgin brass, or fired brass that has been re-sized and fully processed, you are inputting a value substantially lower than the true pressure cell volume and it will distort the outputs proportionally.
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Hoot
Silver $$ Contributor
What I never understood about QL and water measurement is why it tells you to fill the case until its overflowing. Before QL came into my life, I always measured as close to zero meniscus as possible. A Diabetic syringe is great for dispensing small amounts of water as you near the top BTW. Everybody knows a Diabetic who will mooch them a used syringe for science.
Hoot
Hoot
Ned Ludd
Silver $$ Contributor
I personally measure the water volume with the meniscus as flat as possible. In fact, QuickLoad recommends doing exactly that: "...eliminate any bubbles and bring water even to end of case neck" (top of p. 64 in manual). Having the water-filled case mouth backlit with a desk lamp makes doing this relatively simple and very reproducible. I don't agree with the notion of filling the case to the point the meniscus is bulging out of the neck and I don't recall seeing anything stated like that in the manual. That would be measuring case volume that doesn't actually exist. Because we're always going to seat a bullet down in the neck, the true pressure cell volume should be represented by the volume of the case filled to the top [flat meniscus] minus the volume occupied by the bullet of choice at a given seating depth. I suspect the reason QuickLoad recommends filling the case to a flat meniscus at the top of the case mouth (i.e. "even to the end of the case neck") is because it also calculates that specific value; i.e. volume occupied by the bullet, which is based on the dimensions provided in the bullet file. QL then subtracts that value from the total case volume to generate the useable case capacity. Although I don't know this for certain, I'd would also imagine that the key value used by QL for its calculations is the useable case capacity, rather than the total case volume measured to the end of the neck that we input. However, calculating the useable case capacity requires the total case capacity as an input, as well as the volume occupied by the bullet from the seating depth/bullet file. Total case capacity is the easiest and simplest value for the end user to accurately measure, so that is what they recommend, and the program uses that input and the bullet dimensions to calculate the other two volumetric values itself.
There is nothing wrong with determining total case volume for both virgin and fire-formed/processed brass. In fact, I believe that is a good exercise for no other reason than it clearly illustrates exactly what we're doing to the external/internal dimensions of the case as we first fire it, then process it for subsequent firings. I don't doubt that one could get away with using the value obtained from virgin brass, or fire-formed/processed brass as the input for case volume, rather than the value from fired-only brass, as long as they used only one or the other consistently. However, because those values will always be smaller than the value for fired brass, which best represents the true pressure cell volume, the resultant pressure/velocity/case fill output values will also be proportionally (and I would add "incorrectly") higher. I'd imagine from a safety viewpoint, it could be argued that this could be construed as being "extra conservative". Nonetheless, there are other obvious approaches to ensure safety during the reloading process and I would personally like to get the most accurate/reliable outputs from the software that are possible. So I follow the manufacturer's recommendations exactly with regard to measure how to measure/quantify the input values. YMMV.
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Hoot
Silver $$ Contributor
I went with the wording present in the software UI. Here's a screen capture of that portion of the main screen display:
I must have missed that part in the manual and now feel silly.
Thanks for clearing the waters for me.
Hoot
wkdickinson
Gold $$ Contributor
Would adding a drop or two of dish soap to the water to dissipate the surface tension be beneficial?
Drop of Alcohol. Touch the meniscus with a corner of tissue until level with case mouth.
QL does subtract seated bullet volume for an adjusted capacity.
For this, it's better to mind your 'Shank Seat Depth' with a similar boat tail or flat base bullet selected. That's seated bullet bearing. Don't let it figure based on default Cartridge Length and Bullet Length.
Just not as accurate, as bullets change from lot to lot.
On volume measuring at which condition, I agree with Ned.
For me, QL has predicted really well using fully fire formed, unsized case H20 capacities.
But much of that is because I don't FL size.
With this much logged and matched(all else culled), you 'could' then measure for case-to-case comparison of your FL sized capacities(and cull again).
That is, if you really want to get the most out of this -on target.
While FL sized cases hold lower capacity, this information would not provide for accurate QL predictions.
You wouldn't want to use it like you might think.
For example:
You FL size cases, remeasure capacities, and find they lowered by 5gr H2O.
If you then entered this lower capacity, QL would return higher pressure results.
But, the chrono shows that MV from unsized to FL sized cases actually dropped.
It doesn't go up here as QL predicted, it actually goes down.
A QL calibration tweak could be to raise entered overfill capacity a small amount to counter.
This is because some of the load energy is taken up in expanding your FL sized cases further to hit the chamber walls. The pressure curve doesn't take a committed climb upward until the case is actually confined(against chamber walls). And some of the powder is already burned to do that.
This is apparently beneficial, functioning as normalizing results in the face of FL sized capacity variances.
It's full circle back to less need for culling of capacity variances in FL sized cases, and I would not bother.
QL does subtract seated bullet volume for an adjusted capacity.
For this, it's better to mind your 'Shank Seat Depth' with a similar boat tail or flat base bullet selected. That's seated bullet bearing. Don't let it figure based on default Cartridge Length and Bullet Length.
Just not as accurate, as bullets change from lot to lot.
On volume measuring at which condition, I agree with Ned.
For me, QL has predicted really well using fully fire formed, unsized case H20 capacities.
But much of that is because I don't FL size.
With this much logged and matched(all else culled), you 'could' then measure for case-to-case comparison of your FL sized capacities(and cull again).
That is, if you really want to get the most out of this -on target.
While FL sized cases hold lower capacity, this information would not provide for accurate QL predictions.
You wouldn't want to use it like you might think.
For example:
You FL size cases, remeasure capacities, and find they lowered by 5gr H2O.
If you then entered this lower capacity, QL would return higher pressure results.
But, the chrono shows that MV from unsized to FL sized cases actually dropped.
It doesn't go up here as QL predicted, it actually goes down.
A QL calibration tweak could be to raise entered overfill capacity a small amount to counter.
This is because some of the load energy is taken up in expanding your FL sized cases further to hit the chamber walls. The pressure curve doesn't take a committed climb upward until the case is actually confined(against chamber walls). And some of the powder is already burned to do that.
This is apparently beneficial, functioning as normalizing results in the face of FL sized capacity variances.
It's full circle back to less need for culling of capacity variances in FL sized cases, and I would not bother.
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Ned Ludd
Silver $$ Contributor
After I posted that, I was looking further and there is also a place lower on the page where it mentions filling the case to overflow. I would not have used that term after correctly describing filling the case just to where the meniscus is flat because "overflow" seems very misleading and confusing to me. It certainly doesn't have the same connotation as having a flat meniscus.I went with the wording present in the software UI. Here's a screen capture of that portion of the main screen display:
View attachment 1273257
I must have missed that part in the manual and now feel silly.
Thanks for clearing the waters for me.
Hoot
Some people do this, some also add a bit of alcohol. In my hands, both those approaches are unnecessary and increase the likelihood of bubbles, which is undesirable. As long as you are careful to prevent bubble formation, I can't see that such additives would hurt anything, but I have always just used tap water and it works fine.
Loading for the smaller cartridges requires close attention to case capacity and bullet seating. Small changes or incorrect measurements can cause major pressure issues. One needs to double check and make sure all those little Quickload squares are filled in properly. It's very helpful to have knowledgeable folks provide excellent insight into the Quickload program.
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