I agree with what you said, however in my experience I need to do more with weighting factors since I tend to run more over bore capacity rounds. Also shot start initiation pressure as I am usually close to the lands, and certainly with solids.
Quickload help needed
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Mikecr
Well-Known Member
Just keep in mind folks, you can't 'adjust' anything with reloading manuals.
I would not fiddle with weighting factor until you have a fair basis for doing so.
But if you're more towards an extreme in cartridge design either long/skinny or short/fat, underbore or overbore, that's when weighting factor finalizes calibration. For instance, I need WF at 0.4-0.45 for WSSMs, which are very efficient.
0.48-0.5 is likely good for a 22-250.
A 300rum or 30-06 would likely be up at 0.65-0.7, both sending a big slug of powder down the bore, adding to mass of the bullet, and people don't often have long enough barrels for big boomers to improve on this.
A peeve of mine about QL data has been the myriad of cross-sectional bore areas.
I know that test barrels come in every imaginable form, but some loaded in QL are flat out useless for us (much like their unicorn powders).
For any cal, I suggest you load in different cartridges for cal and note the cross-sectional bore area range. Pick a cartridge at peak of bell curve to begin. Don't be concerned that it's not YOUR cartridge. You can adapt any with H20 capacity and weighting factor.
Then, you can later tweak that bore area to cal.
A golden rule with QL is do not adjust anything you're not actually measuring -a lot (just a little each).
You need a good chronograph, and attention to detail for inputs.
I would not fiddle with weighting factor until you have a fair basis for doing so.
But if you're more towards an extreme in cartridge design either long/skinny or short/fat, underbore or overbore, that's when weighting factor finalizes calibration. For instance, I need WF at 0.4-0.45 for WSSMs, which are very efficient.
0.48-0.5 is likely good for a 22-250.
A 300rum or 30-06 would likely be up at 0.65-0.7, both sending a big slug of powder down the bore, adding to mass of the bullet, and people don't often have long enough barrels for big boomers to improve on this.
A peeve of mine about QL data has been the myriad of cross-sectional bore areas.
I know that test barrels come in every imaginable form, but some loaded in QL are flat out useless for us (much like their unicorn powders).
For any cal, I suggest you load in different cartridges for cal and note the cross-sectional bore area range. Pick a cartridge at peak of bell curve to begin. Don't be concerned that it's not YOUR cartridge. You can adapt any with H20 capacity and weighting factor.
Then, you can later tweak that bore area to cal.
A golden rule with QL is do not adjust anything you're not actually measuring -a lot (just a little each).
You need a good chronograph, and attention to detail for inputs.
Mikecr
Well-Known Member
That's not what QL weighting factor is.
It's not an 'overbore' ratio, but a 'bottleneck' attribute.
The bottle necking being what keeps powder burning in or closest to chamber (instead of further down bore, or at muzzle release).
You can have 2 cartridges at the same capacity and cal (like 26wssm and 260), while their appropriate weighting factors are considerably different. That short-fat-higher shoulder angle WSSM burns more of the same load of powder -inside it's chamber.
Like I said, I am open to be corrected...I was going by what I read
How is QL weighing factor estimated?
Pretty much what I do along with using the WF's I sent you and adjusting the BR factor to closely match actual velocities. I also adjust the start pressure. What I've been told to do is if touching lands with cup & core bullet add 7200 psi to the start pressure of 3626 to end up with 10826 psi. For every .001 off the lands then substract 145 psi from the start pressure. This is what I do. I get reliable results doing this. JME
Mikecr
Well-Known Member
It's not estimated or calculated.
It's just a baseline to efficiency, and I imagine it's built into many of QL's calcs.
For different preloaded cartridges they've tweaked it to provide a better baseline, likely as observed.
The intelligent person behind the QL curtain for sure knew that there are practically infinite combinations of individual factors affecting this outcome. Some of which could not be known at the time, or the near future.
Like if I reach back to a Gibbs design and built front ignition into a 30-06, and then went Ackley on it to reduce body taper, and increase shoulder angle. Then for the heck of it, I add neck length. The capacity of this wildcat can exactly equal that of a standard 30-06 if I choose, but you can bet the muzzle velocity will be way different. The weighting factor would have to be tweaked to account for all this, and allow calibration. It's not a problem that my 30thing wildcat is not on their drop down list.
I'll add something else I've learned. You can tell that you have a weighting factor mismatch because it's the only term to cause a pressure and velocity counter, rather than directly following. As OP pointed out, a higher weighting factor causes pressure to go up AND velocity to go down.
If you have a well designed gun and you do pressure testing with webline measure, you can determine when you've hit SAAMI max.
If right there you didn't expect max pressure AND your velocity is reading a bit low (like 50fps) for that pressure, then you can tweak WF to nail your situation. That's good learning, as it saves tail chasing with other guessing of parameters.
It's just a baseline to efficiency, and I imagine it's built into many of QL's calcs.
For different preloaded cartridges they've tweaked it to provide a better baseline, likely as observed.
The intelligent person behind the QL curtain for sure knew that there are practically infinite combinations of individual factors affecting this outcome. Some of which could not be known at the time, or the near future.
Like if I reach back to a Gibbs design and built front ignition into a 30-06, and then went Ackley on it to reduce body taper, and increase shoulder angle. Then for the heck of it, I add neck length. The capacity of this wildcat can exactly equal that of a standard 30-06 if I choose, but you can bet the muzzle velocity will be way different. The weighting factor would have to be tweaked to account for all this, and allow calibration. It's not a problem that my 30thing wildcat is not on their drop down list.
I'll add something else I've learned. You can tell that you have a weighting factor mismatch because it's the only term to cause a pressure and velocity counter, rather than directly following. As OP pointed out, a higher weighting factor causes pressure to go up AND velocity to go down.
If you have a well designed gun and you do pressure testing with webline measure, you can determine when you've hit SAAMI max.
If right there you didn't expect max pressure AND your velocity is reading a bit low (like 50fps) for that pressure, then you can tweak WF to nail your situation. That's good learning, as it saves tail chasing with other guessing of parameters.
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Thank you for the explanation. The only thing not measured that I adjusted in the past was Ba (burn rate) and I normally got results that were close enough for me.
I started reading a lot after this thread was started, about weihgin factor, and I guess I was on the wrong trac.
Shot Start (Initiation) pressure I never messed with, I think I have some more reading to do. I usually host traditional (nosler, BT, AB and PT) and never jammed them. But now I think I have a little more to learn about this.
Again thanks
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This is something I know very little, and in addition to jammed/jump we have to contend with bullet design and material.
Mikecr
Well-Known Member
A solid copper could have a higher engraving force/starting pressure.
I'll tweak it up for normal bullets when at or closer than 10thou off the lands.
I don't know where my bullets will be until full seating testing is completed, but I never run with bullets at or into lands.
All my bullets are WS2 coated as well. So I don't mess with starting pressure to begin with.
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I'll tweak it up for normal bullets when at or closer than 10thou off the lands.
I don't know where my bullets will be until full seating testing is completed, but I never run with bullets at or into lands.
All my bullets are WS2 coated as well. So I don't mess with starting pressure to begin with.
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Here are some descriptions of weighting factor and shot start initiation pressure.
What is weighting factor in QuickLOAD?
The weighting factor is a qualitative estimate of how much energy the powder is using to accelerate the unburned powder with the bullet. A factor of 1 means that all the powder is moving, and 0 means that it all stays in the case during the burn.
Both say to read the bubble help messages in QuickLOAD. I'm not at my computer now and can't include them, but as I recall the weighting factor is lowered for "over bore" cartridges, and raised for straighter wall cartridges.
What is weighting factor in QuickLOAD?
The weighting factor is a qualitative estimate of how much energy the powder is using to accelerate the unburned powder with the bullet. A factor of 1 means that all the powder is moving, and 0 means that it all stays in the case during the burn.
Both say to read the bubble help messages in QuickLOAD. I'm not at my computer now and can't include them, but as I recall the weighting factor is lowered for "over bore" cartridges, and raised for straighter wall cartridges.
I think this is one area where GRT was getting better. It helped you find a Initialization pressure and then calculated your Ba. Waiting to see what will happen with the passing of Gordon.
Carey Farmer
Well-Known Member
Apologies for my first post being such a long one, but Quickload often leaves me scratching my head.
I think we've all seen barrels "speed up" over the first hundred or so shots, even with no change in powder or charge. I recently used Quickload to model this velocity increase in two new barrels, a .264 Win Mag and a 28 Nosler.
Quickload recommends 3625 psi shot start pressure for standard jacketed bullets and 6525 psi for all-copper or fmj / hard core bullets. These are the values I used on the fresh barrels after the initial 25-shot break-in, to determine whether a Ba adjustment was needed for my lot of powder (only very small change was needed).
Over the course of the next hundred or so shots in each barrel, to match the velocity increase I had to increase start pressures by around 7000 psi. After 150 shots fired through the barrels, I settled on 12000 - 14000 psi initiation pressure for all-copper and thick-jacketed bullets (such as Tipped Game Kings or Interbonds), and 9000 - 12000 psi for softer, thin-jacketed hunting bullets such as ELD-X's.
This approach gave good agreement with subsequent observed velocities across a range of powder charges. It also yielded max pressures in good agreement with pressure signs on the softer (Nosler and Norma) cases that I use to develop loads.
As Mr. Weatherby noted sixty years ago, at long enough jumps this problem is diminished. I see lower velocities (therefore lower pressures) at shorter coal's / longer jumps with the same powder charge.
There was a post on Long Range Hunting back in 2009 that addresses some of this: https://www.longrangehunting.com/threads/quikload-start-pressure.44821/
I'm a Quickload novice. Would sure welcome any feedback.
I think we've all seen barrels "speed up" over the first hundred or so shots, even with no change in powder or charge. I recently used Quickload to model this velocity increase in two new barrels, a .264 Win Mag and a 28 Nosler.
Quickload recommends 3625 psi shot start pressure for standard jacketed bullets and 6525 psi for all-copper or fmj / hard core bullets. These are the values I used on the fresh barrels after the initial 25-shot break-in, to determine whether a Ba adjustment was needed for my lot of powder (only very small change was needed).
Over the course of the next hundred or so shots in each barrel, to match the velocity increase I had to increase start pressures by around 7000 psi. After 150 shots fired through the barrels, I settled on 12000 - 14000 psi initiation pressure for all-copper and thick-jacketed bullets (such as Tipped Game Kings or Interbonds), and 9000 - 12000 psi for softer, thin-jacketed hunting bullets such as ELD-X's.
This approach gave good agreement with subsequent observed velocities across a range of powder charges. It also yielded max pressures in good agreement with pressure signs on the softer (Nosler and Norma) cases that I use to develop loads.
As Mr. Weatherby noted sixty years ago, at long enough jumps this problem is diminished. I see lower velocities (therefore lower pressures) at shorter coal's / longer jumps with the same powder charge.
There was a post on Long Range Hunting back in 2009 that addresses some of this: https://www.longrangehunting.com/threads/quikload-start-pressure.44821/
I'm a Quickload novice. Would sure welcome any feedback.
From my observations 14000 shot start initiation pressure is a bit high for any copper jacketed projectile. Solid copper projectiles may possibly be up there when close to the lands. I am planning on working up some 338 LM loads with 255 & 265 grain Badlands ICBM2's this Summer and will see.
I do use the shot start initiation pressure and weighting factor settings in QuickLOAD to adjust things to my velocity and pressure signs. Make sure you measure your case volume and adjust that as well.
