Sprue up - sprue down...

[AtlLaw]

I got to thinking... I know, always a bad thing... 
 
Anyway, there has always been a lot of discussion about sprue flat position when loading BP arms.  In rifles, it appeared to me that more people say the sprue flat should be pointing up, or in the direction of the bullets flight.
 
But I don't think I ever heard anyone say why.     I'd like to know... 
 
As for myself, I always loaded it sprue flat down.  I just thought it preferable, accuracy wise, to keep the aerodynamic portion (round part) of the ball forward.
 
Then, when I got into casting for my hand guns, I realised most of the preferred cast bullets had big flat parts in front!     So, for shooting C&B revolvers, how do you load your balls and why?
 
OH!  BTW... I guess I'm assuming that loading the flat so it would be on the side where the ball would normally engage the rifling is not a good thing for accuracy.   

[Cornbelt]

  I asked that same question in the traditional forum a couple years ago. I got a really good answer.
  Don't have the slightest idea what it was, or who told me, but it convinced me to load spru up, anyhow.

[sidewinder319]

What does it matter? If the ball fits in the chamber mouth its OK.   Once a ball of the correct size is rammed down the chamber shaved and elongated to extend the bearing surface and seal the bore its loaded. This too often asked question is like which is better round or square patches?

[Cornbelt]

  Here is the same question answered several ways.
                 
                      http://www.gboreloaded.com/forums/index.php/topic,35394.0.html

[AtlLaw]

Thanks for the link CB!  Just shows ta go ya that there ain't nothing new under the sun!   
 
Another thing I noticed was that the names of those that replied to that thread aren't familiar.     'cept for Ga-tofu of course!   
 
And thinkin more on it, I 'spect that, in actual practice, ol' Sidewinder may be correct...    I think I'll load sprue up until I have a chance to perform one of my meaningless and statistically insignificant experiments!   

[rdstrain49]

AtlLaw,


It has been proven time and time again that the back of a projectile is more critical to accuracy than the front of the projectile.  I'm sure that it has to do with the aerodynamics of the projectile and the turbulence caused by deformation on the back of the bullet.  It really doesn't matter why.  Any deformation on the front will have a greater effect on accuracy than a similar defect on the back.


All that aside, how can you tell if the sprue is centered down when you can't see it?  Center the sprue up and don't over think it.

[GRIMJIM]

I'm just glad I now know what a sprue is.

[spooked]

Reasoning sez sprue up, cause the sprue is flattened or rounded if loading in a muzzy rifle , thereby more shaping of it. JMO ( don't really know chit about it)..

[curator]

With cast balls, any void or "spongy" area will be directly under the sprue mark. By centering this when loading you insure that the bullet revolves around the imperfection keeping the bullet ballanced. If the sprue has a defect under it and it is not centered it will cause a flier. Imagine the "wobble" of an unballanced bullet at 21,000 to 36,000 RPM. That's the rotational velocity of .375 caliber round ball from a Colt 1851 Navy at 850-1000fps. This is even higher in rifles with slow twist since they attain more velocity. Think of one your tires being out of ballance on the Interstate highway. The only way to be certain the spure mark is centered is when it is up, facing you the loader.

[sidewinder319]

I would like to see you prove this on paper. The sprue is only an issue of loading. Most shooters are aware when loading long arms a sprue can bind in the bore. I have never seen or heard of the rotation of a .36 Cap and Ball not being accurate because of the sprue.  Hell with sights that crude who would know?

[AtlLaw]

I would like to see you prove this on paper.

As would I!  Hi-ebber, and day always be a hi-ebber...
 
I think this would at least fall into the category "If it ain't true it ought to be!"     Most authoritative sounding answer I've heard yet!  I think I'll adopt it so when asked this question I can smile knowingly and... 

[curator]

Sidewinder319/AtlLaw:
 
 My job is not to convince anyone but offer what I know to those who may consider it useful. Take a look at the poeple who are into real round ball accuracy like the people who compete at Friendship and many other muzzle loading rifle/pistol competitions. There is a reason they precisely center the sprue mark on roundballs they shoot and it is not superstition. When a ball is seated with the sprue off center most competitors will shoot it into the berm ranther than risk a flier on their target. After casting a couple of million balls and other bullets I am quite aware of the draw-down and shrinkage at the sprue. Remember, not every ball has a void under the sprue mark, just the ones that hit in the 5 ring despite your perfect sight picture and trigger pull.  I applaud your scepticism but realize some of us are actually on your side.

[Uncle Howie]

...how can you tell if the sprue is centered down when you can't see it?  Center the sprue up and don't over think it.

+1, that's exactly what I was thinking.