Rifling Rate & Internal Pressure ???

Loading Ackley in a bbl. with 1:9 twist rate. Data for this load is run in a bbl. with 1:12 twist rate. My bbl. at 1:9 is 25% faster. Is this going to significantly affect internal ballistic pressure?

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<PaulS>

posted

Genghis,
A tighter twist will place more pressure during the accelleration of the bullet. Will it be significant? Less significant than a bore diameter that is .0002 inches smaller than the test barrel, a chamber that is .002 inches smaller than the test barrel or a throat that is slightly smaller than the test barrel. Now, if one or more of these other items is larger than the test barrel it will reduce pressure in your gun compared to the test barrel.

Just start loads at a recommended minimum and work up slowly watching for accuracy and pressure signs.

PaulS

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stay safe and live long!

<.>

posted

quote:
Originally posted by PaulS:
Genghis,
Just start loads at a recommended minimum and work up slowly watching for accuracy and pressure signs.
PaulS

We should number the "standard remarks" so we don't have to type them out completely

This would be "Number One" . . .

Then we could just post:

"#1, #3, and don't overlook #7 !!!"

I'm being a wise-ass here, but it's sort of true. Yes! Work up loads. Not so much important with "standard data." But we're "wildcat" loading these days, and that's all uncharted water.

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.223 Ackley Improved Wildcat Forum:
http://www.hotboards.com/plus/plus.mirage?who=223ackleyimproved

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