I pose the question to you old heads- is this a good way to sort cast bulets when a scale is not available. Can this be used to help improve accuracy? I find that my Lee mould will throw any where from .635 to .649 length bullets. That adds up to some differance in weight as well as seating depth/ cart capacity changes. As far as diameter it is very close to .452 sizing die I don't alot of metal removed during this process. Generally I've found that .640 is the majority thrown ( 50%),with .645 ( 35%) next biggest portion of say 100 bullets cast. The rest fall +/- .002 either way.
Your inputs please.

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[/b]GUNNUT45

Gunnut45,
            Rather than measure, I visually inspect each bullet for smoothness, being well filled out, and most importantly, the base. As the base is the steering mechanism of the bullet, it should be devoid of any craters or lumps, and have a nice sharp square appearance of 90 degrees. Any deformities, back in the pot they go. The base bottom should have an almost glass like appearance to it. When closing the mold handles between cycles, close them smoothly, to save wear on the mold, and I tap the handle arms lightly, to ensure the mold is closed all the way on my work bench. When using Lee molds, I visually inspect the cavities to make sure they are lined up correctly, before closing the sprue plate. Consistency is everything.

                          Jeff

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Bullet weight and diameter are constant, velocity is always a diminishing variable. I like the hunt to be over after the shot.

That's quite a length variance.  When you measure, are the calipers hitting the sprue cut-off?

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MikeG

Hi, GunNut45:
   I'm still pretty green at casting, but I've found that very few bullets that pass the eyeball test fail on the scale.  Electronic scales don't save you much time when you're weighing powder, but they're absolutely marvelous for sorting cast bullets.

   Mike likely has a point. Is your sprue plate too loose? If you're not hitting the sprure plate at the same angle every time, you could be getting your length variance there.  I wear insulated gloves and push the sprue plate off with my thumb. That gives me a much better feel for how faster the bullet is cooling as well as a consistant push-off angle.

Bye
Jack

Jack

This may or may not help.
Check out two articles from Handloader. The first by Rick Jamison in Handloader #50. The second by Fredrick A. Hohorst, "The Lead Content of Cast Bullet Aloys." They are both in the Wolfe cast bullet book.
In these two articles they compared pure lead to alloys and with a math formulae were able to figure bullet hardness, (Jamison used a chart, Hohorst used a math formula, he's my hero!) it works, but is complicated.
Mr. Hohorst compared Lymans mold #357446.
With known PURE lead under careful conditions the bullets weighed out with 0.3gr difference when weighed in air. When weighed in water the differance was 0.3 gr. The difference in length was 0.0006"
The cavity in the mold was 0.6935" long, the average bullet length was 0.69021.
In a known alloy again under careful conditions the bullets weight variation in air was 0.5gr. In water the weight difference was 0.5gr. The bullet length difference was 0.0011".
As you can see even with a known alloy under very careful conditions there is a much greater difference in bullet length than you would think.
At home with lead alloys that are not as uniform from ingot to ingot there will be an even greater variation in length and weight.
From my experiance with production hunting class rifles I have difficulty seeing a difference in groups with a full 5 grain weight variation in bullet weight.
In heavy barreled rifles with high power scopes I can see the difference and call the impact point of bullets outside the group when shooting bullets of different weight.
The best thing to do is to alloy all of your lead at the same time and ensure that you flux and stir regularly when casting.
I no longer think about bullet length, but I do compare the specific gravity of my alloys and try to seperate them by hardness, as this will effect the uniformity of my bullets and subsequent groups.
When my eyes are uncrossed this is an interesting subject!

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slim