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Old November 17, 2012, 06:44 PM   #22
Lost Sheep
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Join Date: January 24, 2009
Location: Anchorage Alaska
Posts: 2,985
Why increase powder charge when there is unburnt powder anyway?

Quote:
Originally Posted by Pond, James Pond, post 16
Some may say, up the powder charge by a couple of granules, but with unburnt powder, what is the point.
James,

I believe that raising the pressure increases the burn rate, resulting in less unburnt powder. So, a charge with (just pulling figures out of the air) a powder charge where a 10 grain charge that leaves 2 grains unburnt (burning 8) might, if upped to 12 burn all 12 at the higher pressure. (Anyone knowing more about this phenomenon, please chime in.)

Or you could seat the bullet a little deeper (within book values) and see if unburnt powder decreases or velocity increases, or both.

It occurs to me to ask if there is any visible soot on the outside of the cases after firing. That would indicate too-low pressure. (The case does not seal against the chamber walls and propellant gasses leak back. This is more often bound with firearms without a barrel-cylinder gap but does occur in revolvers, too. I have seen it.)

Lost Sheep

p.s. What Jim Watson in post 23 said agrees with my "Modern Reloading" manual. Lead 124 grain bullet, starting load suggested is 5.7 of N-350 (maximum 6.3) and for jacketed bullets 6.2 grains of N-350 (maximumn 6.9).

p.p.s. Grains and granules. Readers of all knowledge levels will read this far into the future and we don't want to cause anyone to mix the two meanings in their thought processes. Granules are the individual flakes or pieces of powder. Grains is how powder charges are quantified. A secondary meaning of grains is, of course, a synonym for granules, but it would not do to mix the terms on the forum.

Last edited by Lost Sheep; November 17, 2012 at 07:38 PM.
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