Do off center spru plate holes affect accuracy?

[.41LC]

In a nose pour will off center sprue plate holes affect accuracy?

[Echo]

Maybe, maybe not. I'm not speaking from experience, but having the sprue cutoff off-center seems like it might affect accuracy - but the only way to really tell is to shoot them...

[Lloyd Smale]

never seen it make a difference as long as the bullet is filled out well.

[Shiloh]

That's been my experience Lloyd.

The one that is off is a Lee six-banger for .45 ACP. The sprue plate pivot screw is slightly off, so the sprue holes furthest away from it are off center.

Shiloh

[chboats]

I had an RCBS 30 180SP 2 cavity. One cavity the sprue hole was centered and other was not. Made it easy to seperate the boolits from each cavity. The boolits from the off center sprue actually were more accurate that the centered sprues in my 308. I don't know why, all measurements and the weight were so close that it shouldn't have mattered.
Also the nose is supposed to have less effect on accuracy than the the base.
The off center sprues on your nose pore should do just fine.

Carl

[AnthonyB]

There is an article in one of the Wolfe Cast Bullet books I got on CD that advocates moving the sprue plate to the edge of the bullet base. Don't remember all the details, but I can look it up if anyone wants - the test results showed better accuracy.
Tony

[Doc Highwall]

No as long as you have a smooth base. If you cut the sprue with a dull sprue plate when the alloy has not harden you could pull material from the base leaving a cavity/pocket. I actually have read where some people have put the holes off to leave a smaller sprue mark. This is a good reason to make sure your sprue plates are sharp.

[deltaenterprizes]

The question is regarding a NOSE pour mold. Nose pour molds are made to insure perfect bases.
I have no personal experience with nose pour molds or or cast bullets in rifles, but I have been told to load cast DEWCs with the sprue up for better accuracy in handguns.

When I first read the post my initial opinion was that it may, but remembering that Sierra 30 cal 168 gr match bullets do not have a perfect noses so it may not.

How far away is your target?

[sixshot]

Using a nose pour style mould I can see where it might if the rifle was accuracte enough to show the difference.
In one of the very early Handloader or Rifle magazines back in the late 60's or early 70's Jim Carmichel was getting best accuracy with small caliber rifle slugs (22-24 caliber) with the sprue plate as far out to the edge as possible. I'm sure someone has that article.

Dick

[AnthonyB]

Should have read back to the original post....
Tony

[.41LC]

Thanks, I won't worry then.

[beagle]

I might throw this in for food for thought.

Voids (bubbles) exist in our cast bullets all over the bullet but are most prevelant in the base of the bullet where the sprue is. Now, any void will cause an imbalance in the bullet in flight and if it occurrs under the sprue cutoff and the cutoff is off center, this will mean the void is off center and will affect the stability of the bullet in flight and hence the accuracy if the spin is not sufficient to compensate for the offset/void.

Many of you think that a perfect base means no void but that's not so.

When we were impact moly coating bullets using metal scrap (jeweler's tumbling media) all bullets had voids. 95% were voided in the base in the vicinity of the sprue cut. Some were on the ogive and some were on the diving bands and a few were on the nose or meplat.

Based on what I saw there, I'd say that an offset sprue plate has the potential to cause inaccuracies. The twist/velocity/rotation speed may overcome it and we may obtain good accuracy but it's still there./beagle

[AviatorTroy]

According to Harry Pope, who did many experiments on the subject, you can significantly damage the nose area of a bullet and accuracy is affected very little. His experiments showed that a bullet damaged very slightly at the base showed significant degradation of accuracy. So I would think you would be fine.

[JeffinNZ]

In my .22 cast bullets I found that reducing the size of the sprue hole GREATLY reduced the weight variations in projectiles. My replacement sprue plates now have 2mm/0.079 pouring holes and variation is 0.1-0.2gr.

[CB Hunter]

In the Wolfe Publishing cast bullet book published several years ago, sorry, don't recall the title and too lazy to go find it, one of the articles was specifically about imperfections in cast bullets and their effect on accuracy. The conclusion was that defects to the point of the bullet had a greatly smaller effect than defects toward or to the base.

Generally I would think the effect of an off-center sprue on a nose-pour mould would be difficult to detect, and voids in the nose have much less effect that if at the base. Basically this is the reason nose-pour moulds exist in the first place.