casting flaw

Kent Shootwell · February 05, 2018, 12:31:48 PM

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

major · February 05, 2018, 12:49:41 PM

When I cast mini's I try to swerll the lead into the hole. This usualy eliminates the void. I use an RCBS Promelt.

Jefro · February 05, 2018, 01:18:46 PM

Heat.....show me the Heat!!

Howdy Kent, I cast 5 different Big Lubes and at least that many for smokeless. I pour HOTTER than most, learned that from Driftwood, a little frosting on the bullet never hurt anything. For 6-cavity BL with a bottom pour Lee I don't start until I hit 825* and often around 900* depending on the caliber and how fast I'll start losing heat. Also I preheat the mold on a hot plate with the last cast still in the mold, makes it easier to do the Bull Plate too cause I'm not losing a bunch of heat. I like to maintain 775*-800* through the session, only the first handful will be frosty. If you have a real finicky mold a touch of 50/50 tin will help. For smokeless I use a Master Caster, heat the mold in place with a hair dryer. About a 10 BH at 740* works fine. Good Luck

Jefro

-Relax-Enjoy

wildman1 · February 05, 2018, 04:32:14 PM

Pour until the mold is full. Then pour some more, let lead run off the side of the mold. The softer (more pure) the lead is the more it will shrink in the mold.
wM1

Baltimore Ed · February 05, 2018, 04:48:59 PM

Solid bullets are not hard but I also had problems with a RCBS hollow base Webley revolver bullet mould. The sprue cutter bolt broke so I need a rebuild kit for that mould now. The swirling sounds like a good technique.

Kent Shootwell · February 06, 2018, 01:35:27 PM

Thanks all, Next time I'm going to peg the heat and hot plate the mold! Reports to follow.

Kent Shootwell · February 06, 2018, 04:46:10 PM

Success! Many variations of pore technique tried and all at 850 degrees finial yielded tolerable results. All visual defects set aside then 35 weighted came out to 3 grain variance. The bulk of them at 519.0 to 520.9 from the Lee 500 grain mold. What worked is a slow bottom pore with the mold 3/8" under the spout.
Now to the range to see if I can get this 1861 rifled musket (Pedersoli) to not keyhole at 50 yards as it has up to now.

major · February 06, 2018, 05:02:07 PM

If your bullets are keyholeing then either your bullets are too small and or the lead is too hard. You need pure lead for Musket mini balls.
Itilian muskets are known for having a large bore size and very often a full .580 or larger. If you can figure out what size the bore is then you want to size your minies to .001 to .002 under that.

greyhawk · February 06, 2018, 11:07:18 PM

Quote from: wildman1 on February 05, 2018, 04:32:14 PM
Pour until the mold is full. Then pour some more, let lead run off the side of the mold. The softer (more pure) the lead is the more it will shrink in the mold.
wM1

What Jefro and Wildman sez x 3
Run it HOT !!! Pour a big sprue and spill some over - needs to keep the sprue fluid until the bit round the base plug solidifies and as the boolit shrinks it can suck that fluid in off the sprue plate - otherwise - well - if the sprue sets first then it shrinks internally and ya get that void on the base plug.
I drill the sprue plate hole out a couple of sizes on all my LEE boolit molds and any others that look too small. Frosted boolits work better than ones with holes an crinkles in em

greyhawk · February 06, 2018, 11:13:50 PM

Quote from: Kent Shootwell on February 06, 2018, 04:46:10 PM
Success! Many variations of pore technique tried and all at 850 degrees finial yielded tolerable results. All visual defects set aside then 35 weighted came out to 3 grain variance. The bulk of them at 519.0 to 520.9 from the Lee 500 grain mold. What worked is a slow bottom pore with the mold 3/8" under the spout.
Now to the range to see if I can get this 1861 rifled musket (Pedersoli) to not keyhole at 50 yards as it has up to now.

More powder!!!!!!!

that dont work try a little stubbie minie
(take and file the nose off of three for a test)

Its a 1:72 twist - a round ball barrel - yeah thats how they made em in the old days - I never understood why - some fellers can get these things to shoot some cant - can be real frustrating - someone posted a good explanating on one of the forums recently (maybe here I dont know) it to do with centre of gravity in the minie - so if you can get that point forward far enough in the projectile it becomes like an arrow - or behaves ballistically like a roundball - so needs very little twist to stabilise - but with a pointy nose and a thick skirt - it behaves like a boolit and 1:72 twist puts it sideways through the paper ---OR ---- crappy lube will do that too.

major · February 07, 2018, 08:30:16 AM

If you still need help with musket problems then the N-SSA would be the place to go. Here is a link to there BB.
http://www.n-ssa.net/vbforum/forum.php

Sir Charles deMouton-Black · February 07, 2018, 09:30:39 AM

Quote from: major on February 07, 2018, 08:30:16 AM
If you still need help with musket problems then the N-SSA would be the place to go. Here is a link to there BB.
http://www.n-ssa.net/vbforum/forum.php

Closer to home you might find the knowlege in The American Plainsman Society.

Coffinmaker · February 07, 2018, 11:29:45 AM

I have a rifle that has Key-Hole'd with everything I fed it. Everything. Then I switched to cast Round Ball and it doesn't Key-Hole anymore. Just a Thought ..

major · February 07, 2018, 02:24:15 PM

Quote from: Coffinmaker on February 07, 2018, 11:29:45 AM
I have a rifle that has Key-Hole'd with everything I fed it. Everything. Then I switched to cast Round Ball and it doesn't Key-Hole anymore. Just a Thought ..

Hay Coffinmaker, I dare you to get a round ball to keyhole!!

LOL

Kent Shootwell · February 07, 2018, 04:37:30 PM

Today's casting with a old Shiloh Products mold produced the right size bullets. Used the same casting routine as with the Lee mold gave a minimum of flaws. Even though they are 15 grains heavier they measure .030" shorter in length. I have high hopes for them. As to shooting round ball, that's crazie talk!

But if anyone can get round ball to key hole I'm certain I did that at a couple of matches judgeing form my scores.

greyhawk · February 07, 2018, 09:47:04 PM

Quote from: Kent Shootwell on February 07, 2018, 04:37:30 PM
Today's casting with a old Shiloh Products mold produced the right size bullets. Used the same casting routine as with the Lee mold gave a minimum of flaws. Even though they are 15 grains heavier they measure .030" shorter in length. I have high hopes for them. As to shooting round ball, that's crazie talk! But if anyone can get round ball to key hole I'm certain I did that at a couple of matches judgeing form my scores.

Whats crazy about round ball - ya get the right patch and ball combo in that barrel ya wont believe how well it can shoot at 100yards .

Kent Shootwell · February 07, 2018, 11:23:45 PM

I have a 58 barrel for my plains rifle which shoots very well with round ball. But this is a 1861 rifled musket and as such I want to shoot it as it would of been used by the the troops back in the day. That requires a mini ball. Having plenty of guns to play with each has its own challenges to sort out and this one is the current test for me.

greyhawk · February 08, 2018, 01:33:04 AM

Quote from: Kent Shootwell on February 07, 2018, 11:23:45 PM
I have a 58 barrel for my plains rifle which shoots very well with round ball. But this is a 1861 rifled musket and as such I want to shoot it as it would of been used by the the troops back in the day. That requires a mini ball. Having plenty of guns to play with each has its own challenges to sort out and this one is the current test for me.

I get it - yes requires a mini ball - also requires massed fire into the ranks at 40 paces - for which purposes a keyholing mini would be admirably suited - (did we just discover their secret

)-----alls I was sayin is that barrel will shoot roundball really well if yo feel inclined (obvious YOU dont - others might?) been there done this - we had a enfield three bander and a mississippi rifle - both with that slow roundball twist 1:72 - both shot really well with roundball and pissed me off no end trying to get a result with minies - sold the enfield and bought a two bander (1:48 twist) - my sons favourite front ender - kept the mississippi rifle and it runs roundball. I still am mystified why the manufacturers persist with that 72 twist when they are set up to machine the 1:48 - it would work so much better and easier for most shooters - more satisfied customers = more gun sales ..........................