Moose 580-450 weights

[Maillemaker]

Here is the weight data for 95 Moose .580-450 bullets that I cast.

The average weight was 445.79 grains, however, as you cans see from the graph there is a distinct taper-off in weights. When I examine those bullets I see no visible voids but very noticeable wrinkles on the surface of the bullets.

These wrinkles in the past would not have been sufficient for me to reject them. But you can clearly see that there is a sharp drop off in weight - over 4 grains of weight from the main line of the group.

When I discard those weights the average becomes 446.67 grains, very close to the advertised weight of 450 grains.

Also when I discard the off-the-curve weights the difference in weights is only about 3.7 grains from the heaviest to lightest, making the bullets highly consistent in weight.

Edit: Oops, I forgot to increase the data range of the graph to pick up the high-end bullets. There was a slight up-tick on the distribution there, so I am discarding all bullets heavier than 448 grains also. When I do this, the difference from highest to lowest is less than 3 grains.

http://i.imgur.com/iPVTLw0.jpg



438.6


439.3


439.6


440.1


440.6


440.7


441.3


441.4


442.1


442.1


442.6


442.8


443.6


444.2


444.2


444.5


444.5


444.8


445


445


445.1


445.2


445.2


445.3


445.3


445.3


445.4


445.4


445.4


445.5


445.6


445.6


445.6


445.6


445.6


445.7


445.8


445.8


445.8


445.9


445.9


446


446


446.1


446.1


446.2


446.2


446.2


446.2


446.3


446.3


446.4


446.4


446.5


446.6


446.6


446.7


446.7


446.7


446.8


446.8


446.9


446.9


447


447


447.2


447.2


447.2


447.2


447.3


447.3


447.3


447.4


447.4


447.5


447.5


447.6


447.6


447.6


447.6


447.6


447.6


447.6


447.7


447.8


447.8


447.8


448.1


448.2


448.2


448.3


448.4


448.5


448.5


448.7

[Rich Foster]

Because of the price of powder and caps and expense of skirmishing I understand wanting all bullets the same weight. But 3 grains of lead is the thickness of a sheet of paper 3/16"x3/16". It should not make much difference and 2 grains is smaller than that. as that said if you want consistant weight bullets control your heat of lead and mould. I contol lead heat with a thermometer and if heat gets to high I throw some sprue cutoffs in pot and have a block of lead to lay the mould on to maintain heat of mould from getting it to hot and I can keep a bullet within 1 grain each way. Just lending something I have learned. Rich

[Maillemaker]

The total weight difference across all bullets was 10.1 grains.

Only when I got rid of the outliers not on the linear portion of the curve did I get down to the 3-grain resolution, which is within +/- .05% of the average, which I think is pretty good.

When I figure out how to plot a normal distribution I'm going to do that and it will make the outliers on either side of the normal more obvious, but for now I just plot them in ascending order and you can see the linear portion of the graph is where most of the bullets lie, and this is your "good" range. Where the values start drooping off or going up are the outliers. I cull them from the data and then I have a good curve that gives me a valid range for acceptable bullets in the future when I weigh them.

There are more bullets off the linear curve at the bottom end of the graph, and I suspect that these are the wrinkled bullets that were thrown before the mold got up to temperature. Visually, they looked good enough to me to shoot - it wasn't until I weighed them that I noticed how out-of-whack they were with the rest of the batch.

http://i.imgur.com/GvQdxva.jpg

http://i.imgur.com/vTU4aC0.jpg