From: Jonathan Spencer, [EMAIL PROTECTED]
>Many interesting comments have been made regarding Vihtavuori powders but no
>real explanation has yet been forthcoming of why I experienced ferocious
>leading with N310 powder but not with Hercules Bullseye - all other
>components in the equation being the same.
Although Vihtavuori place N310 and Bullseye adjacent in their Burning
Rate Chart, as number 2 and 3, the chart does not indicate how close
they are. It may be that N310 burns substantially faster than Bullseye.
*If* this is so, then the pressure (and hence temperature) will be
higher. When a bullet, especially in a pistol, starts to engage the
rifling, it does not commence turning immediately but continues in a
straight line for a while. This results in 'skid marks' on the bullet's
bearing surface. On a lead bullet, this can result in leading on the
driving edge of the lands,
How do the velocities compare?
>Whatever the mechanism that is
>causing the leading, it must be associated with the powder as nothing else
>has been changed. There was no velocity leading in the barrel. The leading
>occurred solely in the cylinder chamber throats (the portion ahead of the
>chambered cartidge) and was fairly uniformly distributed round the chamber
>mouths in all six chambers. The barrel forcing cone and rifling were
>virtually unaffected.
Well, I have to say I don't have a conclusive explanation for this. But
if we consider the sequence of events, in order for the hot gases to
come into contact with that part of the chamber, the bullet is ahead of
that area and the pressure at or approaching its maximum. Could it
result from lead shavings as the bullet jumps the cylinder gap?
--Jonathan Spencer, firearms examiner
"Justice is open to everybody in the same way as the Ritz Hotel."
Judge Sturgess, 22 July 1928
Cybershooters website: http://www.cybershooters.org
List admin: [EMAIL PROTECTED]
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