The Firing Line Forums

Go Back   The Firing Line Forums > The Skunkworks > Handloading, Reloading, and Bullet Casting > Bullet Casting

Reply
 
Thread Tools Search this Thread
Old February 5, 2018, 01:28 PM   #1
Oliver Sudden
Senior Member
 
Join Date: January 7, 2017
Location: Colorado
Posts: 137
flawed mini

I'm a fairly experienced caster but can not seem to over come getting a void in the base of a mini bullet. Note the dark half moon in the photo. I have two different molds that produce the same flaw. These are pure lead as they should be and the molds have been carefully cleaned and pre heated. I've tried casting from the bottom pore both touching and not, ladle pore, as I do for my Sharps, with different speeds of pores. Fine looking bullets on the out side and even if the base cavity looks good the weight varies as much as 20 grains. Ideas?
IMG_0251 by Oliver Sudden, on Flickr
Oliver Sudden is offline  
Old February 5, 2018, 01:41 PM   #2
Chainsaw.
Senior Member
 
Join Date: September 12, 2015
Location: Issaquah WA. Its a dry rain.
Posts: 1,631
Your driving bands/crimp groves look a tad round. Could maybe add a touch of tin without getting the lead to hard.

Pour slower?
__________________
Just shoot the damn thing.
Chainsaw. is offline  
Old February 5, 2018, 07:09 PM   #3
dahermit
Senior Member
 
Join Date: October 28, 2006
Location: South Central Michigan...near Ohio, Indiana.
Posts: 5,260
Preheat the molds hotter still and increase the temperature of your melt. Pure lead needs to be pretty hot to fill out a mold.
dahermit is offline  
Old February 5, 2018, 07:13 PM   #4
res45
Senior Member
 
Join Date: September 15, 2007
Location: NC
Posts: 707
Pure lead in the pot as well as your mold needs to run a bit hotter than wheel weights or other lead based alloys normally will to fill out well, a little tin wouldn't hurt either. Crank the temp on your pot up a bit and see if they drop any better.
res45 is offline  
Old February 6, 2018, 12:37 PM   #5
snuffy
Senior Member
 
Join Date: May 20, 2001
Location: Oshkosh wi.
Posts: 3,054
it's the pin

O.S. the rest of the mold might be hot enough, but the base pin is NOT. Also, as noted, the lead itself is probably not hot enough. Pure lead has to be at least 800 degrees to cast decent. Also as said, about 1% tin would make a huge difference on how well those mini's would fill out without raising the hardness hardly at all. Tin doesn't harden lead much, it just makes it behave much better. You'd still get the skirt to expand to grip the rifling with a bit of tin added to the pure.

Make sure you use pure tin. Using lead-free solder from some sources would add antimony which WOULD harden the mini's. Note the fine print on lead-free solder that says "95% tin--5% antimony. It could also say 5% silver or 5% copper, neither would harden pure much, but the antimony certainly would.
__________________
The more people I meet, the more I love my dog

They're going to get their butts kicked over there this election. How come people can't spell and use words correctly?
snuffy is offline  
Old February 6, 2018, 02:32 PM   #6
Oliver Sudden
Senior Member
 
Join Date: January 7, 2017
Location: Colorado
Posts: 137
Thanks, I'll try going to max temperatures.
Oliver Sudden is offline  
Old February 6, 2018, 05:41 PM   #7
mehavey
Senior Member
 
Join Date: June 17, 2010
Location: Virginia
Posts: 5,074
Run pure lead ~780-800dgr
Do NOT* contact pour. Instead pour about 1/4-1/2" off the hole to vent/alleviate the tendency to form an air pocket near the top of the pin.

*(Go ahead. Ask me how I know)
mehavey is offline  
Old February 6, 2018, 09:57 PM   #8
Oliver Sudden
Senior Member
 
Join Date: January 7, 2017
Location: Colorado
Posts: 137
Made some good slugs today. 850 degree lead, very hot mold and 3/8" from the bottom pore pot. Any other way made voids. Bad part is the stinking mold throws .575" and I need .578 or larger for this rifle. I'll dig out my other mold soon.
Thanks all.
Oliver Sudden is offline  
Old February 11, 2018, 08:18 AM   #9
mehavey
Senior Member
 
Join Date: June 17, 2010
Location: Virginia
Posts: 5,074
If it's pure lead, it should bump up to groove dimension --- no problemmo at all
mehavey is offline  
Old February 11, 2018, 04:09 PM   #10
jmorris
Senior Member
 
Join Date: November 22, 2006
Posts: 2,931
The imperfection at the bottom of the one on the right is what I get from a mold that is not up to operating temperature.

Inclusions on the base of the bullet seem to be worse the larger the sprue is.
jmorris is offline  
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 01:22 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2018 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent: thefiringline.com
Contact Us
Page generated in 0.05264 seconds with 10 queries