Sizing Anomaly

bns454

Active Member
I left some water dropped bullets sit a couple weeks and when I tried to size them,which was near impossible,they come out .0015 larger than usual.Is that normal ? I dont remember this happening before.I sized some I casted today and they come out normal.Its a .500 Cal 600g bullet if that matters.
 

Brad

Benevolent Overlord and site owner
Staff member
Spring back. Harder the bullet the more it happens.
 

fiver

Well-Known Member
yeah, it's common for bullets to grow over time.
sucks when the nose is suddenly hard to shove in a barrel a year or so later after you sat and messed with the alloy trying to get it to fit just right after a months waiting between batches.
 

Ian

Notorious member
If it matters to what you're doing with them, installing checks and sizing the day you cast them and then heat-treating afterwards will restore the dendrite structure to the sized areas (similar to stress-relieving formed or bent steel pieces) and get back what the sizing ruins.

Still, the bullets may grow as they harden even if pre-sized and heat treated afterwards, so watch that too.
 
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OS OK

New Member
This should give you an idea of what to expect from different alloys...
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JWFilips

Well-Known Member
Our Old Departed Friend "William in Waco" had a website where he did extensive testing of the time it took water drop bullets to harden!
What it all came down to was Cast, Waterdrop, and Size! This was the best way to prevent too much spring back. The sized bullets woulds still gain a bit in size in a month or so but no where near trying to resize seasoned water dropped bullets!