QuickLOAD way off from reality. Solutions?

[WildRose]

If you're interested in learning a little more about humidity, here's an interesting observation. Just thought I'd add a little tid bit of info since you were already looking into humidity.

How does humidity affect powder?

You may have heard about a relationship between humidity and bullet velocity either in a book, on a reloading forum, or from a crusty benchrest shooter right after saying they get better ES/SD&#821…

chronoplotter.com

That's an excellent article and explains what I'd observed in difference in the exact same loads after I'd first moved my reloading to a climate controlled building vs uncontrolled building.

I suspected the variance in humidity was effecting my loads because that was the one factor out of my control but had no real way at the time to prove it even to myself.

Once I moved into a THC building my loads became dramatically more stable and consistent.

Once I open a jug though I also throw some extra desiccant into it to ensure exposure to air isn't going to overly affect it.

 

[jimbires]

What is a 'weighting factor' ?

in quickload on the main page , weighting factor is located in the upper left square , down by the "apply & calc" button . is an adjustment for overbore . it helps bring velocity and pressure in to alignment . in this thread there is a formula posted to figure out the weighting factor number . I've never used the formula , I don't know how well it works , or where it came from . quickload says to use .4 for overbore cartridges . most cartridges have .5 in as a default . I was looking at a 223 rem a few days ago , it had a .6 in as default .

RidgeTop , do you use quickload ?

 

[Veteran]

What is a 'weighting factor' ?

Per the Quick Load users manual.

Its the percent of powder instantly combusted in the chamber vs. the percent that combusts behind the bullet as it moves down the bbl.
and is the amount of energy lost due to bbl friction with the bullet, energy loss as heat, and energy loss due to gas blow by which gets in front of the bullet.

If you are using Bergers set back .13 jump, in an old rifle w worn out lands, and using dense pack stick powder like N570 with 95% case fill,
maybe this factor is 55 or 60% im QL?

Thats my understanding from the definition below.

Weighing factor: # Input, represents energy losses from friction, heating and gas leakage; (Default is an estimated value based upon consideration of various cartridge parameters.) Most data records contain a 0.5. This means that 50% of the propellant mass is considered to move with the bullet. For typical cartridges, this is a good figure with which to work, so long as nothing better is available. Refer to the associated Bubble-help (tool tip) window for more information. Wh

 

[Tripodmvr7]

I do not adjust the weighting factor as that reduces pressure when lowered. If you have info where pressure has been measured then you can calibrate and amend the WF so that pressure agrees. Very few instances have however occurred where accurate pressures are available, so I stick with the default WF.

 

[Veteran]

Yes, well your proxy for measuring pressure is velocity.

 

[Tripodmvr7]

The pressures that QL calculates when the speed is used are not very accurate. Speed will be a good barometer, but with new propellants the speed norms for calibres are being exceeded by large margins. I normally calculate nodes that give 50-55K psi for hunting purposes. For target shooting the shooter is advised when pressures approach maximum and it is at his risk if he wants to use that data.

To amend the WF I would want charge, measured pressure and speed obtained. A pity that the propellant manufacturers dont supply all the info needed for QL. That would improve predictability.

 

[TommyBreaux]

in quickload on the main page , weighting factor is located in the upper left square , down by the "apply & calc" button . is an adjustment for overbore . it helps bring velocity and pressure in to alignment . in this thread there is a formula posted to figure out the weighting factor number . I've never used the formula , I don't know how well it works , or where it came from . quickload says to use .4 for overbore cartridges . most cartridges have .5 in as a default . I was looking at a 223 rem a few days ago , it had a .6 in as default .

RidgeTop , do you use quickload ?

Let me say I am NOT a Quickload expert by any stretch of the imagination but I do enjoy using it and Gordon's Reloading Tools.
Let me also say that I don't use Quickload to try to get the maximum velocity out of any cartridge that I load. I use it to try to get the optimal barrel time for the gun I am loading for at the time. Usually there is a window for any barrel length and cartridge where the lowest integer barrel time node with the highest velocity will be above the maximum pressure for the cartridge. Loading to the next higher half node or whole node will usually produce the best accuracy.

The formula I posted earlier in this thread came from a gentleman (?) I met on a Facebook QuickLoad user group several years ago. He said back then that he was writing a book about how to use Quickload with regard to Optimal Barrel Time theory. It hasn't been published yet. Anyway, in Quickload the pull down shows that there is a range for the Weighing Factor from approximately 0.33 for a overbore bottleneck cartridges to 1 for straight wall cartridges. The Quickload default is 0.5, I think this is because the H20 capacities are not specific to your particular cartridge. When applying the formula to most bottleneck cartridges that I load for using an average of 5 to 6 cases for the water capacity I get values that are usually below 0.5. The first thing everyone says is "you can't use the defaults", "you need to measure the water capacity of YOUR cases". If you can measure them why not use them as a constant in the system. As stated earlier the Ba can very from lot to lot but it is provided by the powder manufacturer. So you can either modify the Ba to match your measured velocity of you and alter the starting or initial pressure to match your measured velocity.

The gentleman was quick to point out that once you messed with the weighing factor you really couldn't trust the pressures you were getting from Quickload. His belief and I agree is that as long as you aren't exceeding maximum published velocities from a current manual you shouldn't be exceeding the maximum allowable pressure for the cartridge.

 

[Veteran]

Let me say I am NOT a Quickload expert by any stretch of the imagination but I do enjoy using it and Gordon's Reloading Tools.
Let me also say that I don't use Quickload to try to get the maximum velocity out of any cartridge that I load. I use it to try to get the optimal barrel time for the gun I am loading for at the time. Usually there is a window for any barrel length and cartridge where the lowest integer barrel time node with the highest velocity will be above the maximum pressure for the cartridge. Loading to the next higher half node or whole node will usually produce the best accuracy.

The formula I posted earlier in this thread came from a gentleman (?) I met on a Facebook QuickLoad user group several years ago. He said back then that he was writing a book about how to use Quickload with regard to Optimal Barrel Time theory. It hasn't been published yet. Anyway, in Quickload the pull down shows that there is a range for the Weighing Factor from approximately 0.33 for a overbore bottleneck cartridges to 1 for straight wall cartridges. The Quickload default is 0.5, I think this is because the H20 capacities are not specific to your particular cartridge. When applying the formula to most bottleneck cartridges that I load for using an average of 5 to 6 cases for the water capacity I get values that are usually below 0.5. The first thing everyone says is "you can't use the defaults", "you need to measure the water capacity of YOUR cases". If you can measure them why not use them as a constant in the system. As stated earlier the Ba can very from lot to lot but it is provided by the powder manufacturer. So you can either modify the Ba to match your measured velocity of you and alter the starting or initial pressure to match your measured velocity.

The gentleman was quick to point out that once you messed with the weighing factor you really couldn't trust the pressures you were getting from Quickload. His belief and I agree is that as long as you aren't exceeding maximum published velocities from a current manual you shouldn't be exceeding the maximum allowable pressure for the cartridge.

I use the Chris Long Optimal Barrel Timing Theory which involves the harmonic nodes and how fast they travel in steel vs. the bullet time to exit.

Yes using the bullet time to exit feature of QL and looking at that vs. Long's theoretical nodes is another way to get you into the ballpark for finding the sweet spots. Its perhaps analogous to Satterlee, Audette Ladder, and OCW methods too.

The theory is all rooted in bbl. harmonics.

There are 2 caveats to using this.

First it may get you close to a charge weight and velocity that matches the node from Longs work, but I view it as necessary to then begin shooting 3 to 5 shot groups on either side of it, or Audette ladders, or an OCW test on either side of it. Like Satterlee it may provide a good quick starting place to fine tune from.

Second caveat is you may need a different set of node charts if you have a Carbon Fiber or Stainless bbl. vs. just carbon steel.

Long derived that chart looking at fequency nodes for regular carbon steel I think.

Yet a 4th method for load development...

 

[RidgeTop]

Yes, well your proxy for measuring pressure is velocity.

Thanks for the explanation. If I were to look for that number I would use a Lab Bomb and measure pressure for a known amount of powder. Then, load a case with a X-factor of that powder volume and measure the total pressure when fired. Basic math would show the loss from barrel friction and other factors VS total pressure captured in a Lab Bomb.

 

[Veteran]

Let me say I am NOT a Quickload expert by any stretch of the imagination but I do enjoy using it and Gordon's Reloading Tools.
Let me also say that I don't use Quickload to try to get the maximum velocity out of any cartridge that I load. I use it to try to get the optimal barrel time for the gun I am loading for at the time. Usually there is a window for any barrel length and cartridge where the lowest integer barrel time node with the highest velocity will be above the maximum pressure for the cartridge. Loading to the next higher half node or whole node will usually produce the best accuracy.

The formula I posted earlier in this thread came from a gentleman (?) I met on a Facebook QuickLoad user group several years ago. He said back then that he was writing a book about how to use Quickload with regard to Optimal Barrel Time theory. It hasn't been published yet. Anyway, in Quickload the pull down shows that there is a range for the Weighing Factor from approximately 0.33 for a overbore bottleneck cartridges to 1 for straight wall cartridges. The Quickload default is 0.5, I think this is because the H20 capacities are not specific to your particular cartridge. When applying the formula to most bottleneck cartridges that I load for using an average of 5 to 6 cases for the water capacity I get values that are usually below 0.5. The first thing everyone says is "you can't use the defaults", "you need to measure the water capacity of YOUR cases". If you can measure them why not use them as a constant in the system. As stated earlier the Ba can very from lot to lot but it is provided by the powder manufacturer. So you can either modify the Ba to match your measured velocity of you and alter the starting or initial pressure to match your measured velocity.

The gentleman was quick to point out that once you messed with the weighing factor you really couldn't trust the pressures you were getting from Quickload. His belief and I agree is that as long as you aren't exceeding maximum published velocities from a current manual you shouldn't be exceeding the maximum allowable pressure for the cartridge.

Im a liitle confused by your discussion of weighting factor and case volume inputs in QL..
As far as I know these are 2 separate data inputs and not really that related to one another?

Case volume is just used a proxy for a pressure bomb volume where the explosion takes place.

Weighting factor is concerned with energy losses in the rifle and cartridge system. Energy loss will definitely affect pressure because energy is lost and does not propel the bullet.
Losses are primarily energy lost through heat, from friction of the bullet in the bbl., and from gas blow by in front of the bullet. All of these losses slow the bullets velocity and therefore keep pressure from being higher than it would be if there were no losses. Actually higher bbl friction might make pressure go up.
So its all a net effect I guess

Im not scared to adjust Weighting Factor a little bit based on jump, bullet type etc. It will affect pressure and velocity but its real world stuff.

I believe if I remember the users manual says for Barnes bullets the factor has to be .55 for example.

 

[jimbires]

when I first started to use RL26 in my 7 rem mag . I adjusted Ba to get it to match my velocity . quickload showed my pressure was through the roof , I forget the number but it was crazy high ,something like 80 or 90K psi. . but the rifle showed no pressure , and brass life was great . I put the Ba back to default , and I adjust weighting factor to the 7 rem mag . my velocity output matched up pretty close doing a powder ladder test . the quickload pressure output seem believable . as I lowered the weighting factor number , the velocity output came up , and the pressure went down . this seemed to be what was needed .

 

[Veteran]

I have just posted a new thread on the Chris Long Method of determing Optimum Barrel Time in QL which is related to finding Optimum Charge Weight and shooting small groups.

Using Quick Load for Optimum Barrel Timing and OCW Node Matches

Once you have your QL set up and trued to actual velocities for a range of charge weights at the bullet seating depth you have determined is optimum, you adjust your Ba Burn rate until you history match your actual velocities. You need to be using fire formed brass too. Then you will want to...

www.longrangehunting.com

 

[muzzletalk]

I have just posted a new thread on the Chris Long Method of determing Optimum Barrel Time in QL which is related to finding Optimum Charge Weight and shooting small groups.

Using Quick Load for Optimum Barrel Timing and OCW Node Matches

Once you have your QL set up and trued to actual velocities for a range of charge weights at the bullet seating depth you have determined is optimum, you adjust your Ba Burn rate until you history match your actual velocities. You need to be using fire formed brass too. Then you will want to...

www.longrangehunting.com

I've used this method for years. I can say that at least 90% of the time, it's really close.

 

[ShtrRdy]

I have just posted a new thread on the Chris Long Method of determing Optimum Barrel Time in QL which is related to finding Optimum Charge Weight and shooting small groups.

Using Quick Load for Optimum Barrel Timing and OCW Node Matches

Once you have your QL set up and trued to actual velocities for a range of charge weights at the bullet seating depth you have determined is optimum, you adjust your Ba Burn rate until you history match your actual velocities. You need to be using fire formed brass too. Then you will want to...

www.longrangehunting.com

I've tried this in the past with mixed results. Maybe I didn't go far enough on either side of what QL was estimating for barrel time.