I have a 225415 double cavity mold. One cavity casts bullets .001” larger in diameter than the other.
What is the best way to mark one cavity so I can sort at least part of the time?
I was thinking maybe center punch mark in the meplat. Is there a better way?
Thanks for any ideas. John
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I got a trick from The Art Of Bullet Casting, aiming at getting better filling: offset your sprue plate so that the lead flow “whirls” in the cavities.
One of your sprue marks can be partial and the other full, or one will touch the edge and the other not.
The author was writing about 222(?) and said that the better fill he got beat the effect of an off center mark. I don't know about 222; what I am sure of is that in large caliber pistol moulds, one block will overheat faster than the other that way.
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Wouldn't the sizer die take care of this small discrepancy? I HATE to damage a mold, and in this tiny bullet, a punch mark may unbalance the bullet! Maybe only using ONE cavity at a time would be a better solution. Taking longer to drop a 1000 bullets, BUT they all should be identical! A second ,costlier solution would be having one cavity hollow pointed.
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I've also seen suggestions of filing a small notch in 1 block half at the parting line on one cavity. Just enough to raise a little spot of casting flash. This flash should be small enough to simply scrape off with a fingernail when you no longer need the information.
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Why not just c'punch or scratch the sprue plate ( lightly ) and separate the bullets before gas checking.
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I think “marking” a double cavity mould to differentiate the difference in cavities is the same as boogering up a mould.
I can't imagine that .001 would weigh much more than half a grain. In any case weighing the bullets afterwards to sort for weight would segregate by cavity for the most part.
Weigh a bullet from each cavity first before breaking the center punch out.
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Don't mark the nose of the bullet. That little bump on the nose will tilt the bullet when it hits the seating stem when seating the bullet.
mrbill2
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John, When I got my Brooks mold part of the instructions said not to mark the cavity for orienting the bullet. Instead use a felt tip marker to mark the base of the bullet after cutting the sprue and before opening the mold. Just mark the base of one bullet to segregate cavities. That said I have marked cavities with a center punch. Mark somewhere on the ogive so the punch mark clears the top punch when sizing.
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Thanks to all for your comments and helpful suggestions.
My motive for wanting to be able to sort the bullets by cavity isn't because of a concern about weight differences. I don't weigh bullets. The reason for separating the bullets is that the bigger bullet seems to shoot better. I hope to find a way to find what it takes to make the smaller one work better. If not I will lap out the cavity. In the meantime I would like to keep them separate. I had to laugh at myself when mckg mentioned offsetting the sprue plate. I used to do that 30 years ago with a NEI mold that seemed to cast better that way. I wasn't separating the bullets from the cavities but you are right that is an easy way to tell the bullets apart. Great idea. I also liked the idea that anachronism suggested of filing a small notch at the parting line and causing a bit of flashing. I hadn't though of that. But the offset sprue is even easier. I appreciate the help. John
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on 7mm and up, just put a very small punch mark on a nose cone. on a 22, put a very light axial scratch on a nose cone.
but more interesting would be to take half a day, chuck the mold in a 4 jaw, use a cute little 1/8 full radius boring bar, and cut out a rearward lube groove, heck bring that whole 3 bands out to your max throat diameter.
then you could write a nifty article about how not to follow advice you get on the internet !
ken
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but more interesting would be to take half a day, chuck the mold in a 4 jaw, use a cute little 1/8 full radius boring bar, and cut out a rearward lube groove, heck bring that whole 3 bands out to your max throat diameter.
then you could write a nifty article about how not to follow advice you get on the internet !
ken
What would be needed on that cute little boring bar to turn the mold in the 4 jaw chuck from a flat or round point into something more pointy? John
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pointy bullets .. i would start with a half-flat drill bit about 0.217 ( ? ) dia., get it ground to the shape you want. if possible, shorten the half-round nose to the shortest length needed, these can be pretty rigid.
ken
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If you make the mark on a driving band it will probably rub off when you size the bullet.
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jeff houck
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John Carlson
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sghart3578
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Spindrift
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alphabrass
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MP1886
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