Quick load help

[Klem]

Jasper,

I am not offended, but I am concerned you are providing damning advice about using a program which many others use without issue. Your associated advice about particular loads for Scrape are not the issue.

I find it hard to believe your QL (Quickload, unsure why you use the acronym 'QT', what does T stand for?) has a default 37.5gn water capacity as it is public knowledge that it is 35. An extra 1-2 gns of capacity makes a lot of difference to predicted pressures when loading compressed and on the raggedy edge. Less so if the load is not compressed and conservative. With respect, are you sure you didn't change the capacity while tinkering and unwittinglly locked it in?

I have four Grendel calibres on the pull down menu: two came with the program and two are for my cases. This is for when I am calculating loads for fresh/unfired brass, or fire-formed spent/sized cases. There are subtle differences in the predictions with typically 0.1gn difference when looking at max charges. Also, instead of entering 18" for a Lilja I enter 18.8" which is the actual measured length of the barrel. So GIGO at play here, the more precise the inputs, the more useful the outputs.

I think we all agree...QL will never be exact, and those expecting this are fooling themselves as to what a computer simulation of a gun firing can do. How energetic powder is varies from batch to batch, and also influenced by the ambient temperature - Winter or Summer. You can sort of enter this by enabling the powder data fields and adjusting, but it goes down the rabbit hole of guessing physical data without a laboratory. I have not explored the program to this level of detail but just know loads developed in Winter need to be reconsidered for Summer. Others say the short case confounds QL by primers launching the bullet and temporarily increasing the 'case capacity' before the powder train has burns. For me, knowing how conservative it is and coupling this with manufacturer tables gives the overview I need to maximise internal ballistic efficiency, while not breaking the gun.

I really think you should measure your own case volumes and go with that, regardless of what the QL programmers gave it as a default. There will be a difference.

[Scrape hunter]

Klem my hornady cases held 36.5 grains and my federal cases held 35.2 grains of water .

[Klem]

Klem my hornady cases held 36.5 grains and my federal cases held 35.2 grains of water .

Scrape, OK that changes things. More capacity = more powder before safe load max is reached.

Hornady predicts max load is 29.4gns 8208 @ 102.3% fill, 2,647fps and 51,973lbs at 2.200" COAL.
Federal is showing 28.5gns 8208 @ 103% fill, 2,615fps and 51,560lbs at 2.200" COAL..

Anything over 103% and it is a compressed load. Compress a relstively fast powder like 8208 and even a 0.1gn increments make a big difference in pressure.

Big difference in max loads due to different internal volumes of the two brands. Federal is likely thicker brass and/or a thicker web.

QL is conservative so Barnes advice about 0.1gn more is fair.

Out of interest, how did you seal the cases to measure? Are they brand new cases or used/sized?

[jasper2408]

Here you go Klem. I am running QL 3.9 w/October 2023 update file installed.

Right out of their Readme.txt file from the Sept 2022 update file. I update my program once a year.

To correct predictions is possible to enter a somewhat bigger cartridge case
volume, compared to what actually exists. This causes a corrective effect.
For example, in the .416 Rem Mag, misrepresenting case capacity about
+7% often results in good correspondence with published loading data.

If I enter +7% to the old default 35.99 case capacity for the 6.5 Grendel it comes to 38.4. That is +2.41 grains difference from the largest case that I have measured with water for the 6.5 Grendel. You can change the powder burn rate or the case capacity and QL tells you how to do it to get it to line up with the factory load data. Your problem is that you think that a person can only use your settings to get acceptable data or they are not valid. Yeah, I wish a person could enter the actual case capacity and it lines right up to the factory reload data but it doesn't so a person has to adjust things to get it to line up. QL recommends doing just that. Just read their Readme.txt file and it tells you how to change things to get the data to line up.

I ran Scrapes case capacities that he posted and both of your recommendations are too hot in my version. I used 36.5 and 35.2 case capacities and used all default values for everything else but I did change these two items only 2.200" COAL and 1.510" case length. So there you go. Which person is correct here. Should I tell everybody that you are giving out dangerous information or that you don't know what you are doing?

I have sent an email to QL for them to explain why they increased the default case capacity. I remember seeing something from them about the case capacity was too small and didn't work correctly so they increased it but I can't find it.

Sorry Scrape for hijacking your thread.

[Klem]

Jasper,

Settle down mate, we're having a good discussion here. But we can't if you drift into ad hominem.

[Scrape hunter]

Klem I used fired cases with the old primers left in them from new factory rounds .I'm really glad you suggested that I check my case capacity would have never dreamed that there was ,that much difference in case capacity .Really opened my eyes as to how hard it must be for the people that give us our data to load with ,to do so without liability. Jasper I didn't think you were trying to hijack my thread where all seeking knowledge here if were not we don't need to be here . Much obliged to both of you fellers for your help .Thanks Scrape

[Klem]

Scrape,

All good, I re-seat old primers too when weighing capacity. I also did not know case volumes are so different between brands (I've only ever used Lapua). Makes you think that manufacturer tables will have come from a particular brand of case, which can then be sketchy if a shooter uses a different brand. Obviously there's a margin of conservative built in to all manufacturer recommendations and QL, to avoid accidents and litigation.

Look, I don't have an issue with anyone saying my QL max loads are too hot, or Barnes' recommendations being too hot. Loading at the raggedy edge of a calibre's safety ought to have a margin of safety, not a fine line. And that of course includes the quality of parts in the gun.

So, running the numbers again to compare QL with Barnes' tables...
At Barnes' 2.235" OAL, using your Hornady 36.5gns water capacity (they used Hornady cases), same case trim length, bullet and powder, my QL recommends a max of 29.1gns @ 102.8% fill. 2,639fps/51,956lbs pressure.

Barnes' max is 29.5gns.

If it were me I'd be weighing up how conservative I think both manufacturer and QL are, while appreciating how small differences like case length and volume make big changes in pressure, when using a [relatively] fast compressed powder. Also, it's fair to assume Barnes is telling the truth when they actually tested this. Barnes is empirical evidence, whereas QL is a computer simulation. To my mind both Barnes and QL are close here, so I'd be also close but less than both - I'd use Barnes as the confident benchmark, and QL to do what-if's for things like different seating depths, and in your case, case capacities.

[Scrape hunter]

Another thing that really surprised me was the difference in weight between the two different cases The federals weighed 120.8 grains while the hornady weighed 116.7 grains .I kinda had a feeling I was in high pres. territory when I fired my gun,with the federal cases with 30 grains of powder in them I knew things just didn't feel right.It's good to have a place to come to for help like this forum .

[kmon]

Different brand cases can make a lot of difference. Between different lots from the same company vary some but generally not near as much as between manufactures

[JASmith]

...

If it were me I'd be weighing up how conservative I think both manufacturer and QL are, while appreciating how small differences like case length and volume make big changes in pressure, when using a [relatively] fast compressed powder. Also, it's fair to assume Barnes is telling the truth when they actually tested this. Barnes is empirical evidence, whereas QL is a computer simulation. To my mind both Barnes and QL are close here, so I'd be also close but less than both - I'd use Barnes as the confident benchmark, and QL to do what-if's for things like different seating depths, and in your case, case capacities.

+++1 !!!

...and cross check with other published data from powder and bullet manufacturers. After all, they have a lot to use if they get something wrong either way.

[LRRPF52]

QL can be about 10,000-11,000psi higher than real world in this case when you see figures like 62,000-63,000psi for a load that’s only .5gr over published max, though 8208XBR is known to spike on you once you get near or over max published tested loads.

A lot of factory ammo manufacturers aren’t going to chase the 52,000psi MAP due to variance in MPSM (maximum Probable Sample Mean) and MPLM (Maximum Probable Lot Mean), so it’s better to hug that 49,500-50,500psi space where standard deviation in the samples won’t push over 52,000psi.

If you look at all of Hodgdon’s and Western Powders pressure tested data, you see a lot of max loads that stay well under 50,000psi due to case volume, but they can also be some of the fastest/most efficient load combinations due to the powder efficiency and balanced resistance from the particular projectile.

I also noticed that Hodgdon’s has newer data for 8208XBR under the 107gr SMK that is less than their previous data with that combo. All the components appear to be the same with Hornady case, Federal 205 primer. The previous data I’ve been familiar with all these years lists 29.8C gr under the 107gr SMK at 2,667fps and 49,300psi. The new data lists 28.7C at 2,740fps and 50,600 PSI.

Another bullet that can give us some clues as to where the pressure is, within a certain pressure range, is the 100gr Nosler Partition. The Partitions behave similarly to monoliths because they have a sectional wall inside of them that does not like being compressed, so they resist being driven into the lands and don’t have any bearing surface relief bands cut into them.



Hodgdon’s data for the 100gr Partition and 8208XBR: 28.7gr 2,790fps 50,400 PSI

One thing powder manufacturers will do if you look closely, is avoid pushing near the SAAMI MAP with monolithic bullets (like the 100gr TTSX), due to how they resist being driven into the lands more than cup and core bullets.



Pressure increments average higher as you increase charge weights, so when you mass-produce your lots of ammo, if you chase the maximum listed MAP, you will have more incidence of loads that go over the MAP.

The good thing with a 100gr TTSX is that they aren’t really long like many other monoliths, and they have bearing surface relief bands in them, so they work well with 8208XBR as long as you don’t exceed that maximum published charge weight.

If you have room to work with your COL without jamming the lands, it will help you a little as well.

If you run several ballpark muzzle velocities through a ballistics program, you’ll see that chasing the last .5gr of charge weight doesn’t really give you any practical performance advantage, so it makes sense to err on the side of prudence and stay under book max values for the given COLs.

Hopefully that helps.

[Scrape hunter]

Thanks LRRPF52 good read and good info. .Funny thing got to digging around looking at different data nosler shows what the case water cap. is in there data but there not all the same amount wouldn't it make more sense to use cases with the same case capacity across the board for supplying data to people

[kmon]

I think what Nosler is showing on the case holds water volume includes bullet seated to the tested C.O.A.L not the case volume to the mouth of the case like used in QL. That gives more the actual volume in the case. QL takes the case filled to the amount then the bullet profile and space it takes up in the case in the calculations.

[Scrape hunter]

And how do you think they go about measuring, a compressed load if this is correct Kmon ?I think there using low case fill weights esp. where there is a partition or a e tip involved to cover their hind end from liability.

[Klem]

And how do you think they go about measuring, a compressed load if this is correct Kmon ?I think there using low case fill weights esp. where there is a partition or a e tip involved to cover their hind end from liability.

Scrape,

Who is 'they' in your comment: Nosler, or QL?

If you are referring to QL, it lists the 'Propellant Solid Density' for 8208 as 1.620g/cm[SUP]3[/SUP]. They've either got this from the manufacturer or gone about pouring powder into volumetric beakers themselves.
QL lists the rear of Barnes' 100TTSX bullets as 6.1mm small taper (base), 6.71mm large taper, and 2.54mm as length of taper (between the two). Boat-tail angle is 6.8degrees. With this info and powder density the program calculates the volume displaced for the OAL you enter. You can vary this default data if you want to do your own measuring.

[Scrape hunter]

Nosler