1" bullet mould -

[Cat Whisperer]

AND,

Putting in dowel pins.

Ordered a 100.  Got the reamers + and - 0.001".

3/16 (0.1875") worked well for this size mould.

Drilling 0.010 or so undersize, reaming the pair to press fit and then reaming the top block to slip fit (without chaning setup) and then moving to 2nd hole worked VERY well.  Minor fitting - like removing burs and chamfering the holes.

The two blocks slid together easily and had no easily perceivable movement.

I'll use the same technique for spherical moulds cut on the lathe from round stock.

[and7barton]

I'm assuming you are keeping the lead casting inside the copper jacket, but did you not have the lead coming loose when it cooled down, due to contraction ?
I've been thinking of making similar ammo, but without the aluminium mould - simply pouring the lead into copper pipe-ends. The problem of shrinkage though - can it be solved by pre-heating the copper component ? - I don't know which metal expands the most upon heating.
If, fortuitously, it's the copper that expands the most, then by heating the copper to red-heat, then pouring the lead in, the copper enclosure would hopefully shrink down and grip that lead very tightly.

[Cat Whisperer]

Pretinning I think (hypothetical now ...) would do.  I'm ASSUMING that the copper if not tinned keeps the alloy from getting close to it allowing to be covered and when it shrinks to pull away from it.  If it were tinned then the contraction would pull in metal from the molten pool above it (as when the puddle from the sprue gets sucked down into the mould). 

Surface tension is lessened with additional tin.  A few percent is usually good enough (past which has little effect) for casting the usual rifle and pistol bullets.

I have found casting a lot with 96.5% tin 3% silver and 0.5% copper that a cold mould works best.  Crisp sharp fully filled cavities.  Aluminum and iron moulds.

SO, the next expriment is to tin the inside, cast a few, and then section to see if there are any voids and if so, where.

[Cat Whisperer]

I'm assuming you are keeping the lead casting inside the copper jacket, but did you not have the lead coming loose when it cooled down, due to contraction ?
...

Two of the 7 were loose enough to twist and remove (after cooling).

[Cat Whisperer]

...
If, fortuitously, it's the copper that expands the most, then by heating the copper to red-heat, then pouring the lead in, the copper enclosure would hopefully shrink down and grip that lead very tightly.

Heating copper to dull red (or even to nearly that hot) and water quenching will leave the copper dead-soft - no strength to resist being pulled in by the cooling alloy to which it was bonded.

Water quenching a copper pipe cap may distort it, however.  I think the next step it so simply tin it, cast, and section to evaluate voids.

[Victor3]

...
If, fortuitously, it's the copper that expands the most, then by heating the copper to red-heat, then pouring the lead in, the copper enclosure would hopefully shrink down and grip that lead very tightly.

Heating copper to dull red (or even to nearly that hot) and water quenching will leave the copper dead-soft - no strength to resist being pulled in by the cooling alloy to which it was bonded.

Water quenching a copper pipe cap may distort it, however.  I think the next step it so simply tin it, cast, and section to evaluate voids.

 If you were to drill a few small holes in the tube it would hold the slug.

[Cat Whisperer]

DOH !   

[and7barton]

...
If, fortuitously, it's the copper that expands the most, then by heating the copper to red-heat, then pouring the lead in, the copper enclosure would hopefully shrink down and grip that lead very tightly.

Heating copper to dull red (or even to nearly that hot) and water quenching will leave the copper dead-soft - no strength to resist being pulled in by the cooling alloy to which it was bonded.

Water quenching a copper pipe cap may distort it, however.  I think the next step it so simply tin it, cast, and section to evaluate voids.

 If you were to drill a few small holes in the tube it would hold the slug.

I was thinking - If you slide the copper jacket onto a bit of wooden dowel (held in a vice), and then, with a rounded bit of steel rod and a hammer, ding in a ring of little dents around the tube, that would hold the lead secure against falling out, but it might still rattle a bit, which I don't think would matter.

[Cat Whisperer]

There is even a device consisting of two idler rollers and a form roller that will roll in a canalure (typicall used by those who swage their own bullets).

[lance]

The projos look good ....is that Dalgren rifled?

The Dahlgren is smooth bore. It has an iron barrel that was poured solid, then drilled, and a steel sleeve with welded breech plug.

[GGaskill]

It will be another thread on nose form boring as I figure it out.

I made a half reamer to do the ogive in my mould.  It worked all right in steel but should work great in aluminum.  Its primary problem was trapping chips and thereby scoring the walls.  If you use a shouldered ogive, there would be clearance in the body and the chips wouldn't get trapped.

[Victor3]

There is even a device consisting of two idler rollers and a form roller that will roll in a canalure (typicall used by those who swage their own bullets).

 C-H Die Co. made them. I recently sold one on ebay, but it would only do up to 50 cal. 

 A tubing cutter with the cutting roll dulled to a radius should do the job.

 BTW, I think they'll fly straighter if you only fill ~30% of the tube.