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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Throat erosion and double-based powders.
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<blockquote data-quote="Bart B" data-source="post: 634042" data-attributes="member: 5302"><p>I (and lots of others) figure there's only so much powder you can burn through a hole (the throat of the chamber) in a millisecond and not erode it too fast such that it unbalances bullets by increased gas jetting around the bullet and its rough surface damaging the bullet so it doesn't shoot very accurate. </p><p></p><p>After comparing to top accuracy shooters got for barrel life with different cartridges from 22 up through 30 caliber, the ones burning 1 grain of powder for each square millimeter of the bore's cross sectional area got about 3000 rounds of best accuracy. Cartridges that burned 40 percent more powder got half the barrel life and those burning twice as much got 1/4th the barrel life. Empiracally speaking, its an invese square root law. Short fat cartridges seem to have about the same barrel life for a given charge weight and caliber as long skinny ones.</p><p></p><p>This isn't an exact science nor simple grade school math issue. My formulas only give approximate numbers because the human doing the shooting plays an important part. Some duffer will claim his .30-06 deer rifle barrel's got 8642 rounds through it and still shoots no worse than about 2 MOA at a hundred yards. But top high power competitors rebarreled their sub MOA at 100 yards .30-06 match rifles in the 1960's at 2500 rounds.</p></blockquote><p></p>
[QUOTE="Bart B, post: 634042, member: 5302"] I (and lots of others) figure there's only so much powder you can burn through a hole (the throat of the chamber) in a millisecond and not erode it too fast such that it unbalances bullets by increased gas jetting around the bullet and its rough surface damaging the bullet so it doesn't shoot very accurate. After comparing to top accuracy shooters got for barrel life with different cartridges from 22 up through 30 caliber, the ones burning 1 grain of powder for each square millimeter of the bore's cross sectional area got about 3000 rounds of best accuracy. Cartridges that burned 40 percent more powder got half the barrel life and those burning twice as much got 1/4th the barrel life. Empiracally speaking, its an invese square root law. Short fat cartridges seem to have about the same barrel life for a given charge weight and caliber as long skinny ones. This isn't an exact science nor simple grade school math issue. My formulas only give approximate numbers because the human doing the shooting plays an important part. Some duffer will claim his .30-06 deer rifle barrel's got 8642 rounds through it and still shoots no worse than about 2 MOA at a hundred yards. But top high power competitors rebarreled their sub MOA at 100 yards .30-06 match rifles in the 1960's at 2500 rounds. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Throat erosion and double-based powders.
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