A super boring topic if you aren't a reloader, I know.
I've been fooling around with light .44 Magnum loads, using Win 231 powder, and having a heck of a time getting tight groups. Full power loads all go through the same hole at 10 yards, but light loads shoot multi-inch groups at the same distance.
Anyway, I'd seen this mentioned, and sure enough, the powder position in the case makes a radical difference. With about 6.5 gr. of Win 231, and the powder at the front of the case, I got velocities as low at 659 fps. With it at the back of the case, as high as 830. That's nearly a 50% difference in muzzle energy, and very noticeable to the shooter.
This isn't hypothetical, and it's not insignificant. : )
The problem abates at around 10 grains of 231-- the case is filling up by then, and the behavior is much more consistent.
So I switched to Trail Boss. Problem solved. Though it's a lot more expensive.
Anyway, be aware of this. Charges of fast powder in the single digits (like 5.0 grains or whatever) will not behave consistently. I expect this is a problem down around 3 grains in .38/.357 also.
I've been fooling around with light .44 Magnum loads, using Win 231 powder, and having a heck of a time getting tight groups. Full power loads all go through the same hole at 10 yards, but light loads shoot multi-inch groups at the same distance.
Anyway, I'd seen this mentioned, and sure enough, the powder position in the case makes a radical difference. With about 6.5 gr. of Win 231, and the powder at the front of the case, I got velocities as low at 659 fps. With it at the back of the case, as high as 830. That's nearly a 50% difference in muzzle energy, and very noticeable to the shooter.
This isn't hypothetical, and it's not insignificant. : )
The problem abates at around 10 grains of 231-- the case is filling up by then, and the behavior is much more consistent.
So I switched to Trail Boss. Problem solved. Though it's a lot more expensive.
Anyway, be aware of this. Charges of fast powder in the single digits (like 5.0 grains or whatever) will not behave consistently. I expect this is a problem down around 3 grains in .38/.357 also.