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Old May 19, 2020, 10:27 AM   #1
Gawp
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How to choose the "best" powder from the list given by QuickLOAD

Hi,

I've just bought QuickLOAD and I'm doing simulations for a .30-30 Win Subsonic load (with a 170 gr bullet). I'll shoot it in a Marlin 336 XLR 24" barrel.

I used the "Setup propellant table" feature to basically make QuickLOAD try all powders to get a velocity of 320 m/s (1050 fps), taking into account all the other parameters (bullet weight, barrel length, etc.).

I live in France, so here we can get only very few powder brands compared to the US. I can get the brands Vectan and Vihtavuori.

Below are the powders and charges that:
* QuickLOAD thinks would achieve the 320 m/s
* AND which are officially listed on the websites of the powders manufacturers to achieve SUPERsonic loads with a 170 gr bullet (link: https://www.vihtavuori.com/reloading.../?cartridge=29)



Based on this table, which powder would you pick, and based on what characteristics, to be the safest possible (i.e. avoid blowing up my head or damaging my gun)?
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Old May 19, 2020, 10:31 AM   #2
RaySendero
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I don't like the look of those low percent case fills for any of them.
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Old May 19, 2020, 11:42 AM   #3
zxcvbob
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I would probably use something like Unique or Green Dot. (bulky shotgun and pistol powders) I don't know what that translates to in VV and Vectan. In larger cases like .308 and .30-06, a lot of people use Red Dot for subsonic loads, but .30-30 has a smaller case so Red Dot might be a little too fast; that's why I went with Green Dot.

How about Vectan A1 or A0?
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Old May 19, 2020, 12:57 PM   #4
Gawp
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Quote:
I don't like the look of those low percent case fills for any of them.
Can you elaborate why? In case all powder is ignited at the same time and the pressure is above max?

Quote:
I would probably use something like Unique or Green Dot. (bulky shotgun and pistol powders) I don't know what that translates to in VV and Vectan. In larger cases like .308 and .30-06, a lot of people use Red Dot for subsonic loads, but .30-30 has a smaller case so Red Dot might be a little too fast; that's why I went with Green Dot.

How about Vectan A1 or A0?
Unfortunately I'm not sure what are these powders equivalent with VV and Vectan.

About Vectan A1: good question! I found data in a reloading book suggesting 0,50g of Vectan A1 for a 170 gr bullet (and a 508mm barrel) but... QuickLOAD gives 388 m/s (1273 FPS). So it's not anywhere near subsonic... any idea why? Is it QuickLOAD which is wrong? it's a big difference... :/
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Old May 19, 2020, 01:05 PM   #5
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Does Quickload have A0 and A1 powders in its database? They should be roughly equivalent to Green Dot and Unique (I'm not sure how equivalent, or which is which) Put 1000 fps into QL and see what it predicts. Then ask yourself it if looks reasonable. (always ask yourself if the results look reasonable; that goes for anything in life.)
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Old May 19, 2020, 02:03 PM   #6
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Gawp,

Unfortunately, you would be putting yourself and your gun at some risk using rifle powders at below about 60% of case fill. This can cause the powder to position itself in the case such that a larger surface area is exposed to ignition than is normal, and that can result in the powder burning like a faster burning powder, raising pressure. Every once in a long while it can greatly exceed the normal operating pressure of the gun. Frequently, it also ignites so poorly that it can leave a bullet stuck in the barrel of your gun, bleeding the rest of the gas pressure out around the case. In the best scenario, the pressure will be very erratic.

The best way to handle this is to use a faster powder. Faster powders can be loaded down to 30% case fill before hazards start to appear. You could, for example, use about 6.5 grains of N32C. Because of velocity variation, if you try this, I would pull a small tuft of polyester pillow ticking (stuffing) add insert it over top of the powder to hold the powder against the primer vent (flash hole).

If you would like to see how erratic the rifle powder pressures become, look on pages 52 and 53 of this old study showing the problem in the 30-06. You will see that below about 30 grains of powder (about 57% case fill) the pressures start to go over a span of over 3:1 in some instances. In a later article, in Handloader Magazine, the author explained this is actually a random distribution of a small number of samples, but that in the years after this study the got some less probable events a large number of standard deviations from the average and that could be as much as double the maximum chamber pressure of the cartridge.
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Old May 19, 2020, 03:00 PM   #7
Gawp
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Quote:
Does Quickload have A0 and A1 powders in its database?
They do, but it seems these two powders wouldn't be a good fit: A1 would require a very light charge (0.33g = 5.09gr, for a filling ratio of 23.4%), plus QuickLOAD isn't happy about the default "Shot Start Pressure" (250 bar) with this load and wants to lower it to 191 bar (I'm not sure what this means, but maybe there would not be enough pressure to push the bullet and it would get stuck in the barrel?).

Quote:
Gawp,

Unfortunately, you would be putting yourself and your gun at some risk using rifle powders at below about 60% of case fill. This can cause the powder to position itself in the case such that a larger surface area is exposed to ignition than is normal, and that can result in the powder burning like a faster burning powder, raising pressure. Every once in a long while it can greatly exceed the normal operating pressure of the gun. Frequently, it also ignites so poorly that it can leave a bullet stuck in the barrel of your gun, bleeding the rest of the gas pressure out around the case. In the best scenario, the pressure will be very erratic.

The best way to handle this is to use a faster powder. Faster powders can be loaded down to 30% case fill before hazards start to appear. You could, for example, use about 6.5 grains of N32C. Because of velocity variation, if you try this, I would pull a small tuft of polyester pillow ticking (stuffing) add insert it over top of the powder to hold the powder against the primer vent (flash hole).

If you would like to see how erratic the rifle powder pressures become, look on pages 52 and 53 of this old study showing the problem in the 30-06. You will see that below about 30 grains of powder (about 57% case fill) the pressures start to go over a span of over 3:1 in some instances. In a later article, in Handloader Magazine, the author explained this is actually a random distribution of a small number of samples, but that in the years after this study the got some less probable events a large number of standard deviations from the average and that could be as much as double the maximum chamber pressure of the cartridge.
Hi Unclenick! Indeed, I tried most of the Vectan and Vihtavuori powders in QuickLOAD and N32C seems to be the best fit: filling ratio = 40.5%, charge = 0.41g (6.33 gr), max pressure = 1114 bar (16,151 psi) for a resulting velocity of 317 m/s (1040 fps).

I also tried your trick you told me in my other thread to see what would happen if all the powder would burn at once, and the resulting pressure would be 1518 bar, which is well below the max CIP pressure of 3200 bar.

I have two questions about stuffing and the use of fillers:
* In the case where the pressure generated if the powder would all burn at once is unsafe (> max CIP pressure), then stuffing can be useful to prevent the powder from burning all at once by keeping it in place, right?
* In our case with N32C, stuffing will only help with having more stable/reproducible velocities, right?

Thank you so much for your very high quality and helpful answers Unclenick!
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Old May 19, 2020, 03:12 PM   #8
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Gawp can you get explosia or lovex powder there? It’s Czech made and I would think would be available somewhere. I know they have quite the assortment, and if I recall correctly they have a powder almost akin to trail boss that is safe for reduced loads like what you are looking for.

Edit: found it, but I was wrong it is not much like trail boss. More like in between a magnum pistol powder and fast rifle powder, but safe for reduced loads. D060 lovex powder would be suitable. If you have access.
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Old May 19, 2020, 03:43 PM   #9
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Gawp,

You understand correctly. The N32C can still light at different rates if it is spread out along the bottom side of the case rather than back against the flash hole, but it won't be dangerous. For the other powders, the tuft can prevent the dangerous peak pressure, but you still want to be careful because you have enough powder mass that it can be thrown forward with some force and occasionally you hear of chamber ringing resulting from shooting many loads like that. Also, the slower rifle powders require a certain amount of pressure in the case to maintain combustion through their deterrents in the presence of the combustion gases, so you may need to go to a magnum primer with them. Another discouraging factor for the slow powders is that with the percent of powder burnt in the barrel being so low, they will throw a lot of unburned powder out of the muzzle, which will tend to clog up a suppressor, assuming you are using one.
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Old May 20, 2020, 04:33 AM   #10
Gawp
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Thank you Unclenick, I'll buy some N32C and do some tests then!
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