Quickload

[Ray B]

I don't trust any program to give me a maximum load for my rifle. The bullet & powder companies have all sorts of programs and test results and what any consider a starting to maximum load varies considerably. as such if I'm developing loads for a cartridge I start with obtaining the particulars of the cartridge and rifle and then develop the results with a Powley Computer. this will give me a good starting point and then I can proceed with the actual rifle and cartridge load development.

 

[Jefferry404]

For me, I only use maximum published data to set a reference point in QL. My actual hand loads are usually around minimum loads as this is where I set the OBT node. Not the highest velocity but reasonable groups with a few loads (the Jeffery, Rigby, Gibbs brass getting hard to come by).
I should note that Chris Long was going for the best accuracy by setting his timing at a node null reflection curve where as I set my timing half way between reflections.

 

[Rafiki]

A bit on Load Density ....

The loads I developed and used last year for the 50-90 Sharps were using traditional dangerous game bullets from Hornady and Woodleigh. Those worked well but for my next trip to Africa I decided to use copper monoliths and experiment starting with the values that I’d used for my last safari substituting only the bullet.

Cartridge: 500 Sharps 2 ½” (50-90 Sharps)
Barrel Length: 25”
Case Capacity: 116gr H2O (measured)
Propellent: H335 (82gr)
Bullet: Peregrine VRG-2 (575gr)
Cartridge Length: 3.18”

Peregrine bullets are necessarily longer than traditional bullets of the same weight and also have a geometry that necessitated seating a little deeper in my rifle. These attributes of course affect the usable case capacity.

Using the above values QuickLoad produced the following:

Load Density: 101.7%
Muzzle velocity: 2214 fps
Muzzle Energy: 6204 ft/lbs
Max Pressure: 64328 psi

This was a bit over my comfort level. If we could fully trust these results, which we can’t, in my opinion they are rather high for this cartridge.

The first thing that any user of QuickLoad should do is manually verify the inputs under your control including case volume and bullet length, maximum cartridge length, etc. Free space, the unfilled area between the powder charge and the bullet affects pressure, i.e., as a bullet is seated deeper pressure increases. In the above example the free space represented by the Load Density calculation is 101.7%, a slightly compressed load. That got me wondering if that was in fact true.

I got a 1/2" dowel, filled a 50-90 case with 82gr of H335 and measured the unfilled space from the powder to case mouth as .845". My COAL for this bullet is 3.18" with a seating depth of .714"; So, .845" - .714" = .131" of free space with bullet seated. Clearly QuickLoad over estimated Load Density by a Fairly large factor. I adjusted QL to account for this space by changing the COAL to 3.311" which leaves a new Load Density of 93.8%, down from 101.7% thus having a significant effect on QL's simulation.

Load Density: 93.8%
Muzzle velocity: 2151 fps
Muzzle Energy: 5852 ft/lbs
Max Pressure: 53182 psi

It’s clear that if the volumetric parameters were correct no adjustment to COAL would be needed in order to account for the additional free space. Since I measured case capacity the other volumetric parameter is Bulk Density of the propellent.

In QuickLoad Bulk Density is a volumetric ratio of a propellent relative to water so it is necessary to ensure that this value is correct. To get a correct Load Density number weigh a quantity of the propellent in a known vessel (an empty cartridge case) and change that value in the powder profile in QuickLoad. The Load Density calculation then should be correct in relation to the actual case capacity.

• Find the actual case capacity in grains of water (116gr H2O for a 50-90)
• Fill and weigh the same case with a propellent (129.7gr for H335)
• Find the ratio of propellent to water (129.7 / 116 = 1.118), this is the propellants Bulk Density.
• Update the Bulk Density value in the QuickLoad powder profile.

This can be verified by QuickLoad by setting the COAL to case length plus the bullet length, Setting the Load Density to 100% and then multiplying the resultant grains of propellant by the Bulk Density. That value should be equal to the weight of the propellant used to find the Load Density; in this example 129.7gr.

 

[Sideshow]

I’ve been using Gordon’s reloading tool for a couple of years. Being free it’s good to find the middle ground and I feel that load development is a lot faster as I can See from the program where the accurate loads are. I feel that I don’t need to push it and chase the high end of the scale.

 

[Rafiki]

There is an obvious quasi relationship of velocity and pressure however that relationship is not proportional therefore it is unwise to use velocity as a predictor of pressure. I recently became aware of a formula for “adjusting” predicted pressure that, in theory, would more closely represent real pressure based on observed velocity. The validity of this is the question especially since QuickLoad can only predict pressure based on the very many variables available to it; basically, this adjusts a predicted value to another predicted value.

The observed velocity is more times than not less than its calculated value. In addition to that QuickLoad specifically states that Its calculations are approximately 10% less for the straight walled cartridges that I usually experiment with.

I’m not even going to pretend that I understand how or why this works, or even if it works at all, it’s just one of those things I found somewhere that I thought was interesting. Unfortunately, I don’t have the equipment necessary to measure actual pressure but predicted pressure is not in short supply.

With that understanding the formula is:

Mv = Actual muzzle Velocity
Pv = Predicted velocity
Pp = Predicted Maximum pressure

Pp * (Mv / Pv) ^ 3

Somewhere in this thread I posted some range results from a session with the 500 Sharps 2 1/2" using H335 (80gr) pushing a 575gr Peregrine VRG-2 bullet. My highest actual velocity was 2024fps (2018fps average), not what I was looking for. QL estimated 2151fps @ 59,364psi, 133fps less than QuickLoad’s estimate.

Assuming:

Mv = 2018 fps (average)
Pv = 2151 fps
Pp = 59,364 psi

59364 * (2018 / 2151) ^ 3 = 49,019 psi

If the formula is valid (big “if” there) a lot depends on how accurately QuickLoad calculates pressure based on its inputs, and how accurate those inputs are. The only value we can count on is the observed velocity via chronograph.

Just for kicks I adjusted Ba down to .549 in QuickLoad matching observed velocity which brought estimated pressure down to a comfortable 44,124psi.

Of course this is all hocus-pocus but either way well within the limits of a Ruger No 1 so not too concerning.

 

[Rafiki]

I’ve been using Gordon’s reloading tool for a couple of years. Being free it’s good to find the middle ground and I feel that load development is a lot faster as I can See from the program where the accurate loads are. I feel that I don’t need to push it and chase the high end of the scale.

I also have Gorgon's but have not used it much. I like the interface quite a lot better than QuickLoad but, like QuickLoad its very cluttered. I really need to delve into it and figure out the best way to use this tool. One concern that I have is that the author of the tool has died; the last I heard is that the future is a bit sketchy. maybe that has changed.

 

[Sideshow]

I also have Gorgon's but have not used it much. I like the interface quite a lot better than QuickLoad but, like QuickLoad its very cluttered. I really need to delve into it and figure out the best way to use this tool. One concern that I have is that the author of the tool has died; the last I heard is that the future is a bit sketchy. maybe that has changed.

Yeah it’s a concern, but if you’re just looking for starter loads and can chase around the accurate nodes then I find it works well. Have gotten two very nice lots out of my 7x57 as well as a mates creedmore manbun which he keeps telling me is the round and nut behind the but…..(how do you say it over there) what ever! Lol
I do have a few issues with it but nothing I can delve into here. From what I’ve seen from quick load you would find the same.
If in the future they bin it then I’ll have to use quick load till then Gordon’s is good for me.
As a side note there readings are very close to what my chrony says but I’m still playing it safe any looking for the warning signs.
cheers