22 Cal. sprue plate holes

[WayneS]

 My poll , so I go first,  I'm making some SP out of  1/4" 5056T alum. for the 225 molds I'm going to start  with the .0932 and see how that does, might have to run the melt a bit hotter.
The base of the bullet is the most important part of the bullet and I'm looking for at least  1.5 MOA @ 100 yds

[38-44]

I vote 7/64 because less seems not sufficient to permit a free flow

[shakey]

Might want to read "Purpose of this Forum - ..."

[Veral]

  A FAR more important question is, why on earth would you use the fastest heat transfer metal available for a sprue plate?  Aluminum draws heat from the sprue and sets it up before the mold cavities can solidify, which causes voids in the bullet.  Less so with tiny bullets than large but nevertheless a VERY important concern.

  If you can hit the small hole with the stream from your bottom pour pot, a .1 inch hole is real nice.  The main advantage of a small sprue hole is the fact that there is less metal to shear when knocking the sprue, which tends to deform the bullet base less than a larger on.  It's a matter of area.  For example, doubling the diameter of a hole increases the area by 4 times.  Going up half increases somewhere around double.  Quite a dramatic difference in shear force.

[WayneS]

1st. WHY,  One man's openion is just something we all have and is taken for what the other person thinks of it UNLESS it comes from a very knowledgeable and respected source.  So after re reading the article by C.E.Harris in the American Rifleman anout his "playing" with Alum sprue plates with small [.100] holes I thought I'ld see what the 2nd knowledgable source had to say.

2.  "DITTO" on the Dia. of the hole and  getting as close to as perfect base as possible.