Author Topic: sprue question on cast ball  (Read 2240 times)

Offline adkmountainken

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sprue question on cast ball
« on: March 28, 2021, 11:28:19 PM »
i usually run bare ball through my .75's and they shoot fine BUT fouling becomes a problem over prolonged shooting.  i just got a new to me .735 steel Lyman mold in great shape with plans to run a patched ball through my .75's and experiment.  the mold leaves a sprue that is a tad bigger then normal but not big enough to hit with a sprue cutter. ball rolls right down the barrel so sprue obviously is not a problem and being smoothbore would not be a problem anyways.  i know in rifled barrels most tend to load with sprue up.  i'm guessing it does not makes a bit of difference in a smoothbore??? i did file a few flat but i ran 100 balls today and am not going to file all unless need be.  as i said just want to experiment a little. thoughts?





Offline smylee grouch

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Re: sprue question on cast ball
« Reply #1 on: March 29, 2021, 12:35:08 AM »
Photo of a Jeff Tanner mold (.605 ) showing the small diameter sprue that is cut off with a side cutter at the ball line. When the sprue is cut off there is so little left that it would not alter any flight out of a smooth bore.



Some whaqt poor photo but hope you can see the sprue hole

Offline Scota4570

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Re: sprue question on cast ball
« Reply #2 on: March 29, 2021, 01:58:45 AM »
Put the balls in a tumbler with graphite.  Run them a little while, the sprue will be gone.  The balls will be shiny black. 
 ...pretty. : )

I could not imagine filing the sprues of lead balls. 

Offline Tim Ault

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Re: sprue question on cast ball
« Reply #3 on: March 29, 2021, 01:30:51 PM »
The sprues on the Lee moulds are the opposite a flat spot on the ball . I try to load them either sprue straight up or straight down . Usually up as it's easier to see it

Offline D. Taylor Sapergia

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Re: sprue question on cast ball
« Reply #4 on: March 29, 2021, 07:43:13 PM »
When I shoot rifles, I don't pay too much attention to the orientation of the sprue, when loading.  But with smoothbore, I load the sprue centred and up on the muzzle.  The theory is that when casting, it is possible to have a void in the cast ball which will be the same in all your poor castings.  Placing the void the same way in your bore will eliminate the sphere from being unbalanced in a random fashion, and improve your smoothbore accuracy over the long term.  They say it's crucial in rifles too, but I'm not sure of it.
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Offline smylee grouch

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Re: sprue question on cast ball
« Reply #5 on: March 29, 2021, 08:24:13 PM »
In 1994 I made my first trip to a national NMLRA match. It was a learning as well as shooting trip. When on the Bench rest line I was talking with a round ball bench rest shooter and he told me that he indexed his bullet molds so that the ball was always loaded with the same orientation with the sprue up. His index mark was made at casting because he had a very small shallow punch mark in one mold cavity near the sprue. This very small blemish was lined up the same for each shot.

Offline flinchrocket

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Re: sprue question on cast ball
« Reply #6 on: March 29, 2021, 08:59:00 PM »
Smylee, I noticed that punch mark in your mold and it looked like it was deliberate. I wondered if there was a purpose for that, now I know why. Thanks

Offline hanshi

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Re: sprue question on cast ball
« Reply #7 on: March 29, 2021, 11:33:25 PM »
I primarily cast using Lee molds which don't leave a sprue.  I still sometimes put the "sprue spot" up but mostly pay it no attention.  If there is a sprue I'm careful to center it up in the muzzle.
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Offline smylee grouch

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Re: sprue question on cast ball
« Reply #8 on: March 29, 2021, 11:59:09 PM »
Hi Flinchrocket, yes that was put there by me but because the mold was casting balls that were out of round by 3-4 thousands. It was a 605 and I needed a 610 and had one on order so I thought I would try this out. I shot two targets, 10 shot each with the non-index balls then had some cast after I indexed the mold. Shot side by side alternatly to keep the sun consistent.



I did get a Lyman 610 mold and that cast the right size and my accuracy improved quite a bit so don't need the 605 now. When shooting those 605s I put sprue up with the blemish facing the ramrod.

Offline Daryl

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Re: sprue question on cast ball
« Reply #9 on: March 30, 2021, 05:46:32 AM »
I always index the sprues straight up on both smoothbore and my rifle loading. Yes - it makes a difference in accuracy as shown by smylee grouch.
The method I use to remove the sprues on my Tanner moulds, leaves no sprue to index, but a smooth rounded surface - those are not indexed
in my rifle or smoothbore. One of the postal matches I won, was with non-indexed sprue-less balls in the rifle, but then it was shot at 25 yards and this
 likely made no consequence.

Balls with sprues when shot in a smoothbore, will at some point of the ball's travel (likely when sub-sonic), cause the ball to take on a spin & veer off
target (point of aim). Thus, balls with sprues, if loaded straight up and patched in a smoothbore, if more powder is used to increase the velocity, the range
at which the ball takes on that spin will be extended.

For example, I've witnessed on several occasions, one of the fellow's launched round ball at a 92 yard gong, in the last few yards (it looks) veer off to one side
or the other or down and miss the gong by 3', yet before they veered out of line, were traveling straight to the target in an arc.  I have only observed a couple
launched by Taylor, but they have always traveled straight to the gong. The only difference in loading, is the first fellow used 65gr. 2F in his 20 bore and Taylor
uses 85gr. 2F.
I hit more of the longer range gongs with my smoothbore now that I use patched round balls that have no sprues. I also used 85gr. of powder in the past, but have
increased my charge to 90gr. 2F for trail walks due to the short barrel on my gun.
« Last Edit: March 30, 2021, 08:22:07 PM by Daryl »
Daryl

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