"dirty" barrels??

[jhalcott]

when I use certain powders they leave unburnt powder in the barrel. I was wondering if the 'dirt" is ground into the next bullet OR is it blown out by the compressing air as the bullet travels down the bore? Maybe I just have to much time for thinking lately!

[felix]

Both! The more gentle the ogive, the more percentage of the trash gets driven down, either into the boolit, or into the grooves, or both. Short lands with barrel roughness, for example, will induce the need for the barrel to be manually stroked for accuracy maintenance. ... felix

[HORNET]

Additionally, if you check the older IDEAL designs, many of them had dirt grooves ahead of the first full diameter band. Probably a holdover from BP days. Do they work?? Ya got me, I never noticed much effect that was directly attributable to the presence or absence of the groove.:confused:

[Bass Ackward]

when I use certain powders they leave unburnt powder in the barrel. I was wondering if the 'dirt" is ground into the next bullet OR is it blown out by the compressing air as the bullet travels down the bore? Maybe I just have to much time for thinking lately!

JH,

Since you got the time on your hands, think about what this means to bullet design. :grin:

[45 2.1]

Additionally, if you check the older IDEAL designs, many of them had dirt grooves ahead of the first full diameter band. Probably a holdover from BP days. Do they work?? Ya got me, I never noticed much effect that was directly attributable to the presence or absence of the groove.:confused:

Dirt grooves do indeed work. I have several versions of the 311241, with and without dirt grooves. A healthy dirt groove on a boolit shows much more consistent accuracy than one without it.