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HS6 vs Autocomp burn rate, etc.


KOBGT

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I know someone who loads both in his 9 major open gun, with the same OAL and same bullet. It takes almost a full grain more of HS6 to get the same velocity as the Autocomp. But, according to burn rate charts, Autocomp has a slower burn rate. I am new to reloading, so bare with me, when I ask this, but as you go down the burn rate chart, shouldn't you need more powder not less. Or is there a component to the formula I am missing here....?

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I know someone who loads both in his 9 major open gun, with the same OAL and same bullet. It takes almost a full grain more of HS6 to get the same velocity as the Autocomp. But, according to burn rate charts, Autocomp has a slower burn rate. I am new to reloading, so bare with me, when I ask this, but as you go down the burn rate chart, shouldn't you need more powder not less. Or is there a component to the formula I am missing here....?

Burn rate and powder density/energy aren't correlated.

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Just my experience, it takes more HS-6 to meet power factor than Autocomp. 7.6~7.8gr of Autocomp got me to 168~169pf in my IMM Open, where as I had to go to about 8.4~8.6 with HS-6, and move the bullet way out to make room for the powder. But according to the VV manual, they have the same burn rate.

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Yes Tom, I just noticed the same thing... I hadn't looked at the Hodgdon burn rate chart for a while (my go to) and when I directed someone there I noticed WAC is listed slower than HS6 which I haven't found to be consistent with my data. All things being equal it takes another grain or so to make the same PF. I just tried CFE Pistol which I find to be similar to WAC and they list that slower than HS6 too?!?

What do they have against HS6 all the sudden???

Silhouette is listed way slower than it was as well...

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Burn rate and the charge weight required for the same velocity is poorly correlated. The principle reason is that no two burn rate charts are the same. If you compare different charts, the burn rate thing gets confusing. Even the experts can't agree on where to rank the relative positions of powders from different companies. For example, Hodgdon ranks Unique as faster than A#5. Western says just the opposite. And there are many, many examples where the charts have opposite rankings. Thus, we should not expect burn rate charts to predict charge weight very well. Burn rate charts are general guides, not absolute, and not consistent from one to another.

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Win 540 is now HS-6

Much dirtier then Auto Comp. I bought an 8lb jug from my gunsmith that he had laying around.

They used to use it to make power factor in 38 super etc back in the day. It still works it's just a dirty powder.

I'll use it for steel loads etc, not for major.

Oh, and yes you do need more 540 then Auto Comp to make the same power factor.

I'm using 7.8g of Auto Comp with a 125 Zero JHP and making 174PF out of my 38 Super.

It has 2 popple holes and a 6 port comp made by EGW.

Edited by bigboy69
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I know someone who loads both in his 9 major open gun, with the same OAL and same bullet. It takes almost a full grain more of HS6 to get the same velocity as the Autocomp. But, according to burn rate charts, Autocomp has a slower burn rate. I am new to reloading, so bare with me, when I ask this, but as you go down the burn rate chart, shouldn't you need more powder not less. Or is there a component to the formula I am missing here....?

Burn rate and powder density/energy aren't correlated.

^This.

HS6 is a little dirtier than WAC but the recoil and dot movement is much better for me using HS6. WAC did some weird things to my dot and felt harsher. I would say try them both to see which one is better for you.

Sent from the range

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  • 3 weeks later...

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