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Powder Weights vs Velocity


Fergus

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The reloading tables give minimum and maximum powder weights for a given projectile weight, COL, barrel etc...

Is the velocity increase linear [straight line] between those two points?

Can a person expect to see about the same incremental increase in velocity? [even though a person may be starting at a different velocity than the test barrel]

Just curious.

Dave

Dave, the answer to the question you've asked is yes, for the most part. I've collected quite a bit of data from my chrono sessions and have found that within the useful range of a given powder you can guess pretty accurately using a linear relationship between charge weight and velocity. John Morris just wants to argue :sight: Most of what I load is not listed in any manuals, so I can't comment on their accuracy.

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The reloading tables give minimum and maximum powder weights for a given projectile weight, COL, barrel etc...

Is the velocity increase linear [straight line] between those two points?

Can a person expect to see about the same incremental increase in velocity? [even though a person may be starting at a different velocity than the test barrel]

Just curious.

Dave

Dave, the answer to the question you've asked is yes, for the most part. I've collected quite a bit of data from my chrono sessions and have found that within the useful range of a given powder you can guess pretty accurately using a linear relationship between charge weight and velocity. John Morris just wants to argue :sight: Most of what I load is not listed in any manuals, so I can't comment on their accuracy.

Argue? Nah, more like a spirited debate. :goof:

I wanted him to chime in with my prior post but he must have found a better way to spend his time.

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Not arguing just not making assumptions, it is true that in a narrow range it can seem linear, that doesn't make them linear though.

Kind of like at the end of the night at the bar, ugly chicks seem to look better, they really don't though.

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Kind of like at the end of the night at the bar, ugly chicks seem to look better, they really don't though.

That analogy went right over my head!

Maybe I've been sober too long :)

The OP was not asking for a method to predict velocities from squib to kaboom, just within the range he's interested in.

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Not only that, but I have never been close to the advertised fps with the published starting load.

I've actually found *most* of the hodgdon data to be pretty close to what I've gotten when I chrono'd my loads, with one huge exception. WST data was very accurate for a 230g bullet. But the starting load for a 200g bullet was 150fps below what they listed, and their max load barely got me over major power factor.

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