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Old February 18, 2013, 11:02 AM   #1
BoogieMan
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Making copper bullets

I would like to turn my own copper bullets for my 460xvr. I have CNC lathes and have no problem holding +-.0005 dia which I would think is plenty close for the job. However I dont know what alloys of copper to use. The last thing I want to do is wipe the rifling out of my barrel. Anyone have any experience with this? What would my concernes be? Bullet fragmenting in barrel? Copper fouling the chamber/barrel etc..?
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Old February 19, 2013, 12:37 AM   #2
hornetguy
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I would think that there is NO copper alloy that would wear out the steel rifling in a barrel. The thing to watch for is higher pressures, since the copper doesn't "give" as much as a lead cored bullet does. I think that is why some of the makers of solid bullets machine rings into the sides of the bullet... to give the displaced metal (from the rifling) someplace to go.

I've been giving this some thought as well.. I was thinking more along the lines of brass rod, however.
A screw machine would probably be the berries for this type of job.
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Old February 19, 2013, 01:02 AM   #3
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I believe Hornady has no trouble with "gilding metal" for their solids.

Hornady GMX bullets

I have no idea of the exact alloy Hornady is using, but there's this -

http://en.wikipedia.org/wiki/Gilding_metal

Unless you want "solids" performance (Africa...), the trick might be trying to make and set the absolutely uniform polymer insert so you get expansion.
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Old February 19, 2013, 07:28 AM   #4
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I would think brass to be to hard for a bullet. Other than looking at the case after firing how would measure the pressure?
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Old February 19, 2013, 09:18 AM   #5
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Thank BartB, from another conversation:
http://www.shootingsoftware.com/pressure.htm
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Old February 19, 2013, 09:27 AM   #6
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I would think that swaging for a final size might yield a harder surface while leaving the core soft.

I know from reading the intro in Speer number 9 manual that Veron Speer began making bullets at home using 22 rim fire cases as jackets.

A soft core and a work hardend surface would be my plan.
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Old February 19, 2013, 11:39 AM   #7
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Looks like a pretty complete system. But $800 is a fair investment without doing a little more market research. I can buy a lot of bullets for $800. In order to recoupe the investment I would have to sell a whole lot of bullets after you consider COGS.
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Old February 19, 2013, 07:02 PM   #8
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You didn't say in your OP that you wanted to do it to sell them (?)

No way in the world anyone can manufacture- even solids- and compete with the manufacturers that crank them out in the hundreds of thousands like Barnes and Nosler.

I've read of long-range benchrest shooters turning their own solids for their .50 BMG cannons, but never a .45 pistol round.
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Old February 20, 2013, 08:42 AM   #9
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It wasnt my origanal isea to re-sell. As someone suggested a fair sized investment in pressure equipment and software that would be the only way to recoop that cost.

If I size them the same dia as some factory produced bullets I think I could skip all that. Also are all factory solid bullets swaged to size with a press or is a +-.0005 (half thousandth) close enough tolerance. I dont have any solid factory bullets to mic out.
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Old February 20, 2013, 10:52 AM   #10
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Bullets are actually pretty tight. You can choose either .308 or .3085 or .309 bullets for .30 Caliber, depending what your bore likes. GS Custom in South Africa lathe turns their bullets and claims to hold diameters to within 0.0002", and runout is probably a quarter of that. So it's a precision machining operation. Whatever diameter tolerance you can hold, though, consistency through the run is more important than absolute value. Once you develop a load you don't want to have to change it, bullet to bullet, based on diameter fluctuations. It is unlikely to be dangerous for bullets to fluctuate half a thousandth, but could conceivably mess with accuracy by shifting you off a sweet spot barrel time.

The materials choices are numerous. Soft steel jackets with a 0.002" copper wash are pretty standard in some foreign military ball ammo. Barnes used to make some brass solids. They're discontinued (don't know why), but one of the gun writers said he thought they were among the most accurate .308 bullets he'd ever used. Can't recall who. I got a few boxes from an estate sale that are 165 grain spitzers. A whopping (for a flat base bullet that weight) 1.385" long, but that turns out to be a good length for a 10" twist barrel in a bullet that weight. A little long for a 12" twist. The trusty Mitutoyo's say they are all 0.30740" to .30755", so basically a half thousandth under groove to lessen the swaging effort a bit.

The more modern solid designs have ribs the full groove diameter to lessen the effort of engraving them with the rifling to try to bring it down to that of a regular jacketed bullet. I don't have any to measure, but pick up some Hornady solids with those ribs to get a place to start. Their like having driving bands on an artillery shell. Getting some leaded brass for that might go well.

The trick is to develop the load with whatever the material is.

Do watch out for bullet length. Being less dense, the solids tend to be long. Length is more important to bullet stability than weight of velocity, and you have to have a fast enough barrel twist for it. The stability estimator at the bottom of this page will let you check your designs. Just don't let the Stability number in the result get below 1.4 and you should be OK.

Barnes brass with a jacketed .45 RN to show the color difference better:
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Last edited by Unclenick; February 20, 2013 at 10:59 AM.
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