Why don't charts list fill volume percentage?

[Doyle]

When I started reloading with my buddy, he had Quickload. That software shows percentage of fill volume for a particular load. Judging by the number of recent threads that have discussed loads having too little volume (either causing bad ignition and erratic velocity or easily allowing for a careless double charge), I would think that fill volume would be a factor that people would like to consider when determining which powder to use for a particular cartridge.

However, I see a lack of information regarding fill volume on the various reloading tables I've looked at.

Is there a particular reason table publishers don't want to calculate and publish fill volume? Am I wrong in assuming that it is something reloaders would care about?

[hooligan1]

Im like you man, I like that extra information and I'm glad Nosler has that in their manual, thats what I mostly shoot so...

[Bongo Boy]

I'd be happier if they listed measured peak pressure.

I'm sure producing and maintaining a manual is extremely labor intensive and I can't imagine there's much money in it, really. I find the approach they took with the Hornady manual to be simple, but extremely unsatisfying. Rather than the measured pressure and muzzle velocity obtained with a given load, they list the load that produced a given velocity. So, the muzzle velocities are all 'set' or fixed values (such as 900, 1000, 1100, 1200 and 1300 fps for a given caliber), then the charge weights of various propellants that produce those velocities.

Well, you know right off that those aren't the actual velocities--they may be close but they're ballpark.

So, a complete manual would include charge weights, average muzzle velocity, standard deviation of those measured velocities, average group size from a rest at a given distance, average peak pressure, and case fill percentage.

Let's keep dreaming! I'd actually prefer to produce that data myself anyway, but just can't seem to swing setting up a lab in my garage.

[Nick_C_S]

I load, shoot, and chronograph a lot of target level 38 Special. So I know a little about how low fill levels effect performance. (And I suspect you've read my earlier post from today regarding Vihtavuori N310 .)

From my experience, I'd say that it usually is not much of an issue. I have used Bullseye, W231 (and HP-38), Nitro 100, and AA2 for 38 target applications. They all seem to perform pretty consistently. Now, if you tilt the barrel downward (sending the powder charge away from the primer), bring it back to target, and then shoot, the resulting velocities are usually less.

Some powders will show this phenomenon more than others. But even at that, their performance is still reasonably consistent in terms of velocity and accuracy. AA2 seems to show it the most; which is ironic because AA's website specifically touts AA2 as a "non-position sensitive" powder. The powder that seems to do it the least is W231.

(In my 31 years of loading, it is W231 that most consistently yields pleasing performance - loading after loading; caliber after caliber. But that's for another post .)

And then there's Vihtavuori N310. For 38 Special target, it does not perform well at all over a spectrum of loadings. It just isn't suited for the application. Or at least, that's my recent summation. I believe that of all the powders I've tested, it is only VN310 in which a low fill level manifests itself as a significant performance factor.

All in all, if load manuals gave me this information, I don't know that I would factor it in when selecting a powder.

[Clark]

When I was a child, I spoke like a child, I thought like a child, I reasoned like a child. When I became a man, I gave up childish ways.

Taking inspiration from the bible, when started handloading, I was a novice, I read load books, and I believed them. When I wised up, I got Quickload.

I started handloading in 1999, and by 2001, I see I was posting about Quickload here on TFL.

[higgite]

When I started reloading with my buddy, he had Quickload. That software shows percentage of fill volume for a particular load.

Be aware that the fill volume that QL shows is a percentage of volume under the bullet, not percentage of volume of an empty case. The value varies with seating depth. Just because QL shows a percent fill of 60% does not mean a double charge will overflow the case. Just thought I'd throw that in.

[Clark]

I don't know for sure until I do it, but for comparison in quickload I assume 100% for ball power, 105% for stick powder, and never mind in flake.

[Real Gun]

Fill volume is something I care about, at least for being able to readily see the charge in a case before placing a bullet for seating. I simply refer to the VMD chart supplied with the Lee Auto-Disk powder measures. This is how I reacently figured out that Trailboss would work for me to attain a charge that would measure within the minimum aperture size for the Lee Measure. 2.0 gr of Trailboss worked nicely for 32 SWL and 78 gr bullet, but I have since found that the Bullseye load would also fit. Also I determined that my desire to use AA#5 with 32 H&R would require getting the MicroDisk from Custom Cast, since the lowest charge of that dense powder that the Lee could measure was 4.8, when I needed 3.0 or less.

I like to fill big bore cases and appreciate that most of the time the magnum powders are filling up the case nicely, I presume by design. Trailboss or IMR 4227 in 45 Colt is another one, the biggest case I load.

[T. O'Heir]

Because it's irrelevant. QuickLoad is a program written by somebody who very likely has never fired a real firearm. There are far too many variables for any program to be even close to accurate.
In any case, the percent of volume will be different for every manufacturer's cases as they're all slightly different. You do not load differently for one brand vs another. It makes no difference to anybody except the bench rest guys.

[BigJimP]

Fill volume is also irrelevant...because it varies so much ..from powder to powder.

What matters is the consistency of the ignition ...and the consistency of the velocity...( so how the powder ignites, how it burns ( is it fast or slow and everything in between) matters a lot !)

As long as its a published recipe ( primarily from the mfg of the powder I'm using -- not the bullet company )...and it fits into the case, I'm fine.

[Clark]

I started handloading 308 with 168 gr SMK and IMR4895 in 1999.
My first online post about Quickload was 9/23/00.
http://en.wikipedia.org/wiki/QuickLOAD
I now hand load ~65 cartridges.
I have ~ 44 powders.
I am always doing something new.
The fill percentage feature is very important to me.
If I do a calculation of all powders at the same or less peak pressure, and have the results sorted by velocity, I don't want slow powder with 150% fill ratio lurking at the top of the list.

The only powders where I actually measured the density were Power Pistol, Bullseye, and surplus 4895. With the other powders, I just go with the density that comes in the quickload library.

[Jimro]

Doesn't Unclenick have a nice picture comparing the case fill of two 30-06 loads with the same charge of IMR4064, but one used a drop tube and the other didn't?

I think that might be why you don't find much fill % data, along with case volume differences, it just doesn't seem like a data point that would be very useful for either safety or accuracy.

Jimro

[RaySendero]

BigJimP wrote:

Fill volume is also irrelevant...because it varies so much ..from powder to powder.

I found this to generally be true. Only exceptions I've run into were :

A reduced load for my wife's 36-06 showed increased velocity variation as the load was reduced below 85%.

Compressed loads in my 458. Switched to a powder funnel drop tube to get more powder in case w/o having to add as much seating force and also helped stabilize the crimp (hold).

[Brutus]

I've been using Quick Load for just a short time. Seems to work great for low pressure target loads, always right in the ball park as far as velocity goes.
Having trouble with the hotter loads for instance a 10mm load using 13.8 gr. AA#9 with a 180gr XTP shows over 1400fps. and produces dire warnings.
Hornady's 5th. claims it's a safe load and actual chrno readings yield 1250fps.
Sent an E-mail to Ed over at quick load but have yet to receive a reply.
Measured the case capacity of a Winchester case at 24.3gr of H2o, but that just made it worse.

[Shootest]

Why don't charts list fill volume percentage?

I don't know about the newer ones but, my older Nosler manual does list fill percentages for each load.

[Snyper]

I'd be happier if they listed measured peak pressure.

That's another meaningless number since it only applies to that one specific round, that day, in that gun.

It tells you nothing about what your results will be

[Unclenick]

Originally Posted by T. O'Hier

Because it's irrelevant. QuickLoad is a program written by somebody who very likely has never fired a real firearm. There are far too many variables for any program to be even close to accurate.

You sometimes you contribute good stuff, but other times you make these uninformed pronouncements based on assumptions that just a little homework would tell you are not a correct. I recommend you download the free demo version of QuickLOAD from NECO. Read the manual. You will learn the author was a handloader already when he first created the computer algorithm in the late 1960's at the Technical University of Darmstadt working with military anti-aircraft guns and laboratory data on those guns to validate it. So he has had access to the best data collection and been handloading for close to 50 years. His career is in the arms industry and he circulated the code among friends inside the industry for 20 years before those friends pushed him into making a version available to handloaders. He writes code for the CIP and is a well respected European ballistics authority. Dr. Ken Oehler suggested Herr Broemel had seen far more real firing data than he, Dr. Oehler, and others combined.

As to case fill, it can matter a lot in some instances and little in others. It just depends on a variety of factors. I fired a lot of LC NM '64 ammunition in testing rifles at one point. The charge of 4895 filled the case just over 80%. I got about 80 fps velocity difference and went from round primers to flat primers just depending whether I tipped the chambered rifle to put powder forward, away from the primer, or back to have the powder over the primer. If you stayed in one position and your bolt operation threw the powder in the same place each time, the accuracy wasn't bad for the lot I had. But as soon as you have to shoot up or down hill or if you had to change the handling positions of the rifle in a match, it was a poor load for long range. At 1000 yards it represented over 2 feet vertical difference in point of impact.

But it gets worse. Writing in the 1995 Precision Shooting reloading guide, Dan Hackett described a load that worked fine when he loaded it at home, but which produced sticky bolt lift when he loaded it at the range. He finally figured out that in transporting the powder from home, the vibration of the travel was packing the stick powder down. That lowers its burn rate and reduces peak pressure and final velocity a bit.

Years ago I pulled down a box of Federal GMM .308 Winchester with 168 grain SMK. It had a slightly (≈0.5%) compressed load of IMR4064 at the time. No doubt its famous consistency is due in part to that compression locking the powder volume in place and preventing transport vibration from changing the load performance.


Brutus,

What happens in a lot of short straight wall pistol cases is that as you get the case more full with a slower powder that produces maximum velocities is the primer will make enough gas to unseat the bullet and start pushing it into the throat of the rifling before the powder burn gets well underway. This causes a stall in the pressure rise from the powder burning and gives expansion a head start. QuickLOAD does not have a direct way to compensate for that. You have to seat the bullet artificially far out to compensate for it when it happens.

In this instance, if I use Accurate's data for the XTP, they seat it to 1.250", and have a maximum load of 13.5 grains, and show a pressure of 34,100 psi (oddly, that's a little over either SAAMI or CIP maximum) and get 1242 fps from a 5" test barrel using a WLP primer. If I take that bullet seating depth out by 0.1 inch, to 1.350", I get a prediction of 33,945 psi and 1260 fps, which matches their data pretty well. The SAAMI drawing for the cartridge and chamber show there is plenty of room for such a jump. The actual jump may, indeed, be over 0.3 inches, but the actual compensating number will generally be somewhere in between actual and maximum possible COL as the powder burns during the the jump.

The Hornady data goes to much heavier loads than the Accurate data allows for. There are several reasons this could be. As Hartmut warns in the introduction to QuickLOAD on page 5 of the manual:

5. Never shoot someone else's handloads.
6. Be aware that 'canitser-grade' propellants differ from lot-to-lot. From lot-to-lot there might be totally different powders of different origin in the canister.

QuickLOAD manual, p. 5

Well, Hornady doesn't use a SAAMI standard pressure gun like Accurate did in its tests. Hornady used a Colt Delt Elite. These can be quite loose, especially after some extended use. Hornady uses a slightly longer (+0.010") seating depth. Hornady uses a Hornady case, where Accurate uses a Winchester case. With .308 Win, Hornady cases I've measured have more water capacity than Winchester, and that may also be the case with their 10mm. No way to know without measuring it.

Bottom line though, since Hornady didn't use a standard pressure test barrel, I consider their data to be their handload, developed with pressures signs from cases and primers, which are not very reliable and which can vary a lot with the chamber they are fired in. Usually Hornady data is on the low side, but the exception disproves the rule, and in this instance, I would not personally trust their data as much as Accurate's. Part of the reason for that is the gun difference, but part is that I know Accurate powders have changed sources in some instances over time (as they, themselves state explicitly with regard to Nitro 100), so I expect Accurate's data to reflect the most recent sourcing of powder but have no idea how recently the powder used by Hornady was sourced.

This is why we always try for multiple sources of load data before trusting one. I can also find pressure tested data that is closer to Hornady's numbers in the Lee manual, so, again, this powder may have changed. My personal approach would be to stick to the most conservative data until I had measured velocities with my gun to see if they come close to the published data. (That's after allowing for any difference in barrel length. QuickLOAD can give you that difference estimate very nicely.)

To the OP's question: One of the problems with case fill is if varies with powder lots. The only distributor that gives that data is Western Powders. They distribute Ramshot and Accurate and give bulk density, bulk density tolerance and VMD's for all their powders. Looking through the accurate site and clicking on a powder you will find some vary in density by ±5.6% from lot-to-lot. So no VMD table or bulk prediction for that powder can be counted on to be more accurate than that. So what you have to do is measure it for yourself.

To make that measurement, take a fired case and weigh it. Then fill it with room temperature water full to the mouth with no meniscus, no air bubbles iside, and no water drops stuck to the outside of the case, and weigh it again. Subtract the first weight from the second and multiply the result by 0.065* to get the case water capacity in cc's. Let the case dry for a few days. Weigh it again to be sure it is dry. Charge it with powder the way you usually do it, but this time to overflow. Level the top at the case mouth with the edge of a card. Weigh it again. Subtract the case weight. Divide the number of cc's you got from the water weight measurement by this new number of grains of powder to get the VMD. Divide the number of grains by 15.432 to get the number of grams, then divide that by the number of cc's to get the bulk density of the powder in grams/cc.

Stick powders are different. How you dispense them can greatly change their bulk density by changing how the powder particles pack together in the case. At the earlier suggestion, my photo of the same charge of 4064 put back into the same case through different length drop tubes illustrates this:



Spherical powders typically show much less difference with drop tubes or vibration packing. Actual spheres tend to find highest packing density automatically. The very spherical H380, for example, changes very little with drop tube loading.


*This factor is for water at about 75° F. It allows that water density at that temperature is about 0.997 gram/cc and that a gram weighs 15.432 grains.

[F. Guffey]

Before the Internet there were suggestions when selecting powder. One suggestion: select a powder that comes closes to filling the case. For me that presented a problem. Like the wise 'K-Mart shopper' I have selected powder based on the price, and, the number of rounds I could load per pound.

On another forum, they were discussing obsolete powders, the topic was 3031. I had pruchases an eight pound can of IMR 3031, I shared two pounds of the eight with local reloaders. I had already looked at burn rates for powders and knew 3031 is faster than 4895 'MEANING' I was going to be using less 3031 than 4895, that meant I was going to have more room between the top of the powder and bottom of the bullet.

Then there are those slow powders, I always look for the 'C' as in Crush.

Then there must be fluffy powders that are not as dense and weight less by volume.

F. Guffey

[Brutus]

Thank you very much for the insight Uncle Nick what you say makes a lot of sense however when I apply the same parameters you did 1.25 O/L 13.5gr of AA#9 I get 59,866psi. @ 1419fps. I have my case capacity set to 24.3gr. of
H2o which may be part of the problem but that's the actual capacity of the Winchester case I measured. How does one input primer data? Sorry to be a pest but I just got into this and find it intriguing.

By the way if I seat the bullet out to 1.360 I get the velocity I chornographed. In your experience would you say this represents the true ballistic profile for my pistol using this particular powder?

[Unclenick]

Originally Posted by Unclenick

In this instance, if I use Accurate's data for the XTP, they seat it to 1.250", and have a maximum load of 13.5 grains, and show a pressure of 34,100 psi (oddly, that's a little over either SAAMI or CIP maximum) and get 1242 fps from a 5" test barrel using a WLP primer.

Brutus,

Understand, those numbers are all from Accurate's published load data. I had to seat out to 1.350" in QuickLOAD to get a comparable result.

In your case, yes, I think seating out in QuickLOAD is a much more realistic representation of the powder's actual performance in your gun if it matches your muzzle velocity with your barrel length. It's just compensating for primer unseating. Be aware that if you change powders, due to the changed burning characteristics, you may have to use a still different seating depth.

Nick

[Brutus]

Sounds reasonable but where do you draw a practical cutoff point? I would think any more than .100 would be stretching it. Unless, of course you can fit a .45 Colt case in your 10mm.

[Real Gun]

Then there must be fluffy powders that are not as dense and weight less by volume.

And cost more...a jar of Trail Boss is only 12 ounces, but the price compares to a pound of anything else.

[Unclenick]

Brutus,

You should be able to tell. Set up a load with the bullet sticking way out. Plunk it. Keep nudging it deeper until the head of the case is level with the barrel extension plus whatever amount the gun has as a gap between the back of the extension and the breech face. Throw in another couple hundredths for a good jam into the rifling. See how much longer that is than the seating depth you have now for good feed.

[Brutus]

Thanks again for the tip. I'll give it a try.