H4831 vs H4831sc

DiabeticKripple

DiabeticKripple

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I did a search since I remember reading about it, but I cant find the threads.

Has anyone switched from H4831 to H4831sc?

Im shooting the 120gr TTSX at 3300fps with H4831 but the case it quite full and I bought some H4831sc to see if I could bring the powder level down out of the neck.

Should I completely rework the new load (72.0gr) from scratch, or start somewhere close (70-71gr) and see what it does?

I get its the same powder, same weight and density so theoretically the leftover case volume is the same, just the kernels are closer together resulting in less crunching with the bullet.
 
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If you have compressed one load IMO you have changed the burn rate.


H4831 and Short cut for my loads are pretty much identical. Non of my loads has one that is compressed though.
 
It should be directly interchangeable with the difference being something along the lines of lot to lot variation. But as stated above, compression rate could alter things. I'd try loading a few rounds stepping up to your current loading to check pressure and velocity just because. As in a single round per charge. If it's doing what it's supposed to, then load up 5 and check accuracy. Make the call from there.
 
AS above. It's close enough to use the same published data as a guide. A different lot number means you back off some and work it up again. How you do that is your decision but I would back off 3 gr and work up in 1/2 gr steps. Then do your accuracy check.
 
OP, some powders seem to prefer slightly compressed loads. H4831 is one of them.

I don't know why this happens, maybe Ganderite will chime in.

Like others here, I don't prefer to compress the powder charge, but reluctantly admit, compressed powder loads often produce the best results.

My preferred load density with H4831 or H4831ssc is just touching the base of the bullet, whether the bullet base is above or below the neck.

H4831 types of powder usually have a lot of wiggle room so whatever is working and it isn't broken, don't fix it.
 
jethunter said:
AS above. It's close enough to use the same published data as a guide. A different lot number means you back off some and work it up again. How you do that is your decision but I would back off 3 gr and work up in 1/2 gr steps. Then do your accuracy check.
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That's why I blend all of the different lots of the same designation powder into one big lot and add every new lot upon purchase. This gives me about the best consistency I can hope for on burn rates and have never had to change a load, unless I'm changing the primer from one type to another, or new cases, or different bullets, or different rifle/barrel.

I have a 30-06 load, using H4831 with 200 grain bullets, for a specific rifle, that I haven't changed in 50 years. The only thing I changed was I started using magnum primers.
 
All of the published load data I've seen says that you can use these powders interchangeably. This seems counter-intuitive to me given the abundance of research addressing compressed/vs non compressed, and the availability of oxygen.

I find it hard to believe that a compressed 4831 has the same amount of free oxygen in the case as a SC with room to spare. I guess the difference is so marginal that none of experts thinks it matters.

That said, I have never found a single application where the switch from 4831 to SC or vice versa had no effect, and in all cases adjustments were needed. As far as I am concerned, they are similar, but different powders. I don't start completely from scratch on the load development, but I always approach as if I need to make an adjustment, same as switching to new lot.

I like Bearhunters idea of having a witches brew of lot numbers. As long as its adequately mixed every time you add a new lot, it should dilute the variations in lot among the entire batch. I've never noticed a big difference between lots of modern power anyways, so this seems good to me. Will investigate if there is a way to make this happen with my bench set up. Not sure I have something big enough to handle mixing 20-30 lbs in one go, and don't love the idea of a massive quantity of powder in a big open container.

Would like to hear more about how you actually do that.
 
Cameron SS said:
All of the published load data I've seen says that you can use these powders interchangeably. This seems counter-intuitive to me given the abundance of research addressing compressed/vs non compressed, and the availability of oxygen.

I find it hard to believe that a compressed 4831 has the same amount of free oxygen in the case as a SC with room to spare. I guess the difference is so marginal that none of experts thinks it matters.

That said, I have never found a single application where the switch from 4831 to SC or vice versa had no effect, and in all cases adjustments were needed. As far as I am concerned, they are similar, but different powders. I don't start completely from scratch on the load development, but I always approach as if I need to make an adjustment, same as switching to new lot.

I like Bearhunters idea of having a witches brew of lot numbers. As long as its adequately mixed every time you add a new lot, it should dilute the variations in lot among the entire batch. I've never noticed a big difference between lots of modern power anyways, so this seems good to me. Will investigate if there is a way to make this happen with my bench set up. Not sure I have something big enough to handle mixing 20-30 lbs in one go, and don't love the idea of a massive quantity of powder in a big open container.

Would like to hear more about how you actually do that.
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I have read the same, and my result show you are right.Similar but they are different by quite a bit. In my 6.5-284 , max I can get is 49 grains of H4831 before pressure sign abound. With the SC, 53.3 grains was the max.
This is much more than lot to lot variation. I threat them as different and reworked my load, witch at the end, SC gave me better accuracy , more velocity and lower SD, at 52 grains.
 
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Smokeless gunpowder does not require any free oxygen in the case to burn properly.
I have had some loads that were so highly compressed that they threatened to push
the seated bullet back out of the case. [7mm STW/H5010, 7x57/IMR7828, et al]
Never have had an issue with combustion consistency. Dave
 
Cameron SS said:
All of the published load data I've seen says that you can use these powders interchangeably. This seems counter-intuitive to me given the abundance of research addressing compressed/vs non compressed, and the availability of oxygen.

I find it hard to believe that a compressed 4831 has the same amount of free oxygen in the case as a SC with room to spare. I guess the difference is so marginal that none of experts thinks it matters.

That said, I have never found a single application where the switch from 4831 to SC or vice versa had no effect, and in all cases adjustments were needed. As far as I am concerned, they are similar, but different powders. I don't start completely from scratch on the load development, but I always approach as if I need to make an adjustment, same as switching to new lot.

I like Bearhunters idea of having a witches brew of lot numbers. As long as its adequately mixed every time you add a new lot, it should dilute the variations in lot among the entire batch. I've never noticed a big difference between lots of modern power anyways, so this seems good to me. Will investigate if there is a way to make this happen with my bench set up. Not sure I have something big enough to handle mixing 20-30 lbs in one go, and don't love the idea of a massive quantity of powder in a big open container.

Would like to hear more about how you actually do that.
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Cameron, when powder burns in the case, it produces everything it needs to keep burning, once the primer ignites it.

There was an article in American Rifleman about 40 years ago, done by the US Army and likely the Soviets, where they were checking the results of firing cartridges in vacuums. The US even tested a cannon from outer space in orbit.

Sorry Dave, I replied to Css post before I read yours.

By the way, I found that I get better velocities and accuracy in my 7x57s with H4831, but every rifle is an entity unto itself.
 
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bearhunter said:
That's why I blend all of the different lots of the same designation powder into one big lot and add every new lot upon purchase. This gives me about the best consistency I can hope for on burn rates and have never had to change a load, unless I'm changing the primer from one type to another, or new cases, or different bullets, or different rifle/barrel.

I have a 30-06 load, using H4831 with 200 grain bullets, for a specific rifle, that I haven't changed in 50 years. The only thing I changed was I started using magnum primers.
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in this case I wouldn't mix H4831sc with regular H4831.
 
Eagleye said:
Smokeless gunpowder does not require any free oxygen in the case to burn properly.
I have had some loads that were so highly compressed that they threatened to push
the seated bullet back out of the case. [7mm STW/H5010, 7x57/IMR7828, et al]
Never have had an issue with combustion consistency. Dave
Click to expand...

Yes the chemical composition of the powder has plenty of oxygen already by design. That doesnt render the remaining air in the case inconsequential. If the experts think it doesnt matter than its probably because its only of marginal utility.

That said in handloading it can often be those marginal differences that have a big effect on precision.

BH, Would love to read those studies if you have a link.
 
jethunter said:
in this case I wouldn't mix H4831sc with regular H4831.
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I fully agree, they aren't the same designation on their containers, so it doesn't happen.

However, I did try out a half dozen rounds of 7x57 with SSC and regular mixed in equal proportions and used the same accuracy load with regular H4831 and there was no difference in POI or velocity spread. Still, it's not a good idea, but I had my curiosity bug scratching and just had to find out.
 
Cameron SS said:
Yes the chemical composition of the powder has plenty of oxygen already by design. That doesnt render the remaining air in the case inconsequential. If the experts think it doesnt matter than its probably because its only of marginal utility.

That said in handloading it can often be those marginal differences that have a big effect on precision.

BH, Would love to read those studies if you have a link.
Click to expand...


I'll see what I can find. It was only recently on the SCI channel that they mentioned the cannon in outer space and it's trials, that made me even remember those old articles.

https://youtu.be/uYEteSfnObc

https://youtu.be/HNyXbdkTF-k

https://youtu.be/F7qqHDViFko

https://youtu.be/iG8Ag3OYTz8

https://youtu.be/xerdC6hN7x8
 
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im not compressing the powder that much, but the powder was right up to the neck of the cartridge.

my Varget load for 308 is VERY compressed, if i use a drop tube i can get it about halfway up the neck.

As for the leftover case capacity after filling, it should be the same whether you use H4831 or H4831sc because the powders are the same, just the sc is more efficient in taking up an absolute volume. The volume between kernels is smaller, thus leaving more room at the top of the case. The density is the same, and we weigh charges, so the exact same amount of powder is going into the case.

I will back down a bit and work up to the same velocity and see if the accuracy remains.
 
bearhunter said:
I fully agree, they aren't the same designation on their containers, so it doesn't happen.

However, I did try out a half dozen rounds of 7x57 with SSC and regular mixed in equal proportions and used the same accuracy load with regular H4831 and there was no difference in POI or velocity spread. Still, it's not a good idea, but I had my curiosity bug scratching and just had to find out.
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SC meters better, why mix it with the long cut. Kind of silly.
 
just an update to the thread,

i loaded up some rounds starting at 69.5 all the way up to 72.5 and a bunch at 72.0

same velocity as the H4831 load, and the same group at 72.0. I put 3 rounds all touching at 100m.
 
jethunter said:
SC meters better, why mix it with the long cut. Kind of silly.
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Just to satisfy my own curiosity. Nothing more and it's not a thing I would do on a regular basis.

However, I would mix different lots of H4831 to get one large lot of H4831 and I would do it with any other powder I use a lot of.
 
bearhunter said:
Just to satisfy my own curiosity. Nothing more and it's not a thing I would do on a regular basis.

However, I would mix different lots of H4831 to get one large lot of H4831 and I would do it with any other powder I use a lot of.
Click to expand...

You musing about it might make a new reloader think it was a good idea to mix the regular and sc versions. Just clarifying for the less experienced.
 
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