Was discussing with Paul making bullet squeezing dies. Said I would dig out my die and mangle some 7mm's down to .277, well as it happens couldn't find the :cens: thing.
Oh well make another....ah and that is the cone drill I was yapping about Paul.

So, how did you get the hole to 0.277" or 0.276"? Is it correct to assume, based on our conversation, that you 'honed' the transition from the 'forcing cone' to the final ID?

I don't THINK I've seen one of those drill bits that wasn't stepped. I have ordered a .375" carbide burr with a "round-nosed tree" shape. I'll see how that works before I look for the above drill bit over here.

Paul

PS - https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Cone+drill&_sacat=0
Nuthin' but stepped.

Paul

This burr has a max diameter of 0.375" and a draft of 14 degrees. (Based on looking at it, I think that angle is inclusive.) That sounds 'good' for this exercise since I start with a bullet 0.358" in diameter. The 'trick' is getting the final hole precisely right - 0.337" or o.3375".

Paul

I can buy (locally) a 6' stick of B7, 7/8-14 All-thread for $90. At 3" per die, that's 24 dies, and $3.75 each. Beats $25 for a blank from PTG or MidwayUSA, but theirs are prettier. Each grade 8 2.25" bolt (what I'm currently using) costs $5. The $3.75 isn't that much of a break really. I am planning to make dies for making bullet jackets from copper tubing though, so the $90 stick is worth considering.

Paul

That tapered cone burr worked like I knew what I was doing for the 'first stage'. Bullets are now down to 0.344". I have to get a drill that will get me somewhere between 0.337" or .338". An 8.6mm drill is 0.33858", which, after springback of about a thou will be too big I think. An 8.5mm drill is 0.33465" which leaves about 0.003" to "polish" out. Three thou is a lot to polish out of steel.

Still, VERY pleased with the cone burr! Made making the first die trivial.

Paul

So I got tired of waiting for the 'right' tools, and 'filled me boots' as joe_bloggs would say.

I drilled the next die to 21/64th or 0.328" and used the cone burr again to create the taper. I make a gauge so that I could tell when I got to exactly where I wanted the ID to be - 0.3375". I used a small (chain-saw sharpening) rat-tail file to knock the necessary 0.0095 inches out. Took about half an hour of 'filing' with the workpiece (die) in the lathe and holding the file. File a little, see if gauge fits. File some more. See if gauge fits. Finally it fit. I polished the inside with a "greenie" (abrasive pad) chucked in a hand-held drill. Came out perfect - 0.3380".

I have one 9mm and three .357 pistol bullets. The 9mm is 95 grains, and two of the .357 bullets are 110s, and one is 125. I swaged 5 of each to 0.338.

In the picture below, you can see the two swages, the gauge laying in front of the dies, a small pan full of the swaged bullets, and one example of each bullet behind the dies.


Here's the caliper's 'read' on the final diameter:


I am using the ram from my Lee .323 sizing die. I think I will make a ram specific for each die. That will prevent any little 'flange' from forming on the rear of the bullet as the jacket squeezes down past a small ram.

The 7/8-14 bolts cost me $5 each. The burr cost $18 delivered. So something like $30 for the pair of dies. Lee will make custom sizing dies for $65 each and a delivery of "6 weeks".

Now I need to make dies for forming bullet jackets from copper tubing.

Paul

QuoteNow I need to make dies for forming bullet jackets from copper tubing.

Waiting for that one...

Well since I will be relying on you for guidance, you'll be the first to know.

Paul