Bullets for 9.3 x 72R Drilling

[Diz]

For those of you who wonder how these tools were made I thought I would post the process. I usually try to find junk or orphan dies at the gun shows to buy cheap. I stay away from chromed or nitride coated dies as well as carbide as they cannot be drawn down soft enough to machine easily. At least that is my experience.

I pack the parts in my furnace crucible with fine charcoal before putting them in the oven. This prevents them from scaling during the process and doesn’t seem to add any carbon as bone charcoal does. I heat them to about 1480 – 1500 degrees Fahrenheit for several hours until they are fully soaked through then I turn my kiln off and let it cool on its own to room temperature. This takes about twelve hours. After that they are usually soft enough to work with ordinary high speed cutters.

This die had a straight .250” diameter hole through it to begin with so all I had to do was center it and drill it through with a 23/32” (.3594”) drill. The hole finished at .360” which left me with .005” or so to clean up. Using the tool shown below I finished boring the hole to .364” and left a thousandth to polish out later. Then with the same too I cut the recess for the point die to fit into. For these parts I usually use standard bolts usually grade five as they are easy to cut. With this cutter ground the way it is I can bore into a shoulder and then face off square without changing cutters or position. You have to be very careful as you approach the bottom so you don’t jam the tool and get a bad chatter. I bored it to just clear the finished outside diameter of the point tool and the depth I needed for support and to make the point. After that I could take the body tool out of the lathe.

93x72R Lathe tool I.jpg

Next I rough cut a ½” bolt so I would have enough shoulder to true and machine the point. I held the bolt in the chuck by the hex, trued it up and center drilled the end. Then I faced it off using a regular lathe tool. Next I drilled it through with a 3/16” drill. This hole would be the ejection hole and give me clearance for the point tool.

93x72R Point lathe tool I.jpg

The tool above is hand ground to the shape that I want the point to form. You can move it around a bit to get it just right but it is sort of a trial and error thing. The first one I made was too “pointy” and I didn’t care for it. With the ejection hole it is a simple matter to plunge the point tool in a little at a time until you have both the depth and diameter you want. In this case I wanted the diameter right at .357” or the starting size for the bullet I was using. I ended up with .358” finished and I was happy enough with that. At least nothing broke or chattered or went too wrong.

For the point plug I started with a #12 bolt and roughed it off to the length I needed then chucked it up and filed it to fit the hole. When it would just go in I trimmed it flush with the end of the point radius. The last thing was to center a 3/8” bolt long enough to make the bottom punch and turn it so it would just fit into the body die. Everything got polished up a bit and that was that. I may color harden them later but they could work for years unhardened.

They are not very pretty but they work. I lube the bullet with bullet forming lube from Rich Corbin and then press it in my shop press. These bullets are soft and don’t take a lot of pressure to reform. After that I drop the die between two bars so it is held by the shoulder and press the bullet along with the point die out of the body die. The bullet is now stuck in the point die but I clamp it in my vise and pull the ejection plug out. This usually comes out very easily. Then with a 3/16” punch I knock out the bullet. It leaves a small indent in the end of the bullet but doesn’t hurt anything. Slow and easy gets it done.

Thanks, Diz

[Nathaniel Myers]

Fantastic, that's exactly the kind of post I was hoping you would put up.

You have a system that obviously works well for you. If I may make a suggestion or two. First for annealing, if you wish to simplify your process (this depends on your furnace or you mentioned kiln?) you may look for heavy gauge aluminum foil (it's actually stainless). There are a few names for it, heat treat wrap is one. When heat treating die details (A-2, D-2, etc) we would tightly wrap the parts is a heavy brown paper bag. Then the parts were wrapped in aluminum foil. This aluminum foil is thick, you can't tear it with your hands, but a GOOD pair of scissors will cut it. Wrap tightly folding the ends, and with the ends folded, slightly hit them to seal the pouch. During the heat treat process any oxygen that may be in the pouch is burned oxidizing the brown paper bag and not your part.

You may try making some of your tooling out of O-1, I do apologize if your familar, but it is very easy to heat treat for "home" work. Though personally I make everything out of PH4140 or A2 and send it out for HT.

O-1 heat treats and annealed nicely, and then polishes up beautifully. In fact, I may have some scrap laying around I could send you.

As well as "bargain" bin dies. If any of you need a die to modify, let me know I usually have a pile.

Very nicely done!

[sharps4590]

Fascinating, wonderful.....you guys are so far ahead of me the difference is laughable.

[Diz]

Sharps, I have a feeling you are far more adept than you let on.

Nathaniel, Yes your suggestions are all well taken and I am glad you brought it up. I am not an expert on heat treatment by any means and I have only recently ventured into color hardening. I am sure there are others who are far more experienced but for the sake of discussion I think all this is very worthwhile even though it doesn’t directly pertain to German guns themselves. These things do affect the ability to shoot and enjoy them and I would like to think there is an interest there.

To be honest I try to stay away from oil hardening steels only because the stink-up the place and I have a hard time controlling the quench temperatures during the winter. My shop is unheated and things get cold out there. My water quench tank will freeze! I just completed a small project of hardening some A-2 parts for a fellow and did it as you suggest with air tight packets. However I use stainless steel foil I buy from an outfit in Ohio called All Foils. They have .002” 304 stainless (plus other alloys) just for the purpose. They only sell it by the roll so it can be a bit expensive to start but far cheaper than any other I have found. Brownells is frightfully expensive for the same stuff. I like it because it is very tough and difficult to puncture but you can cut it with scissors and double folding the seams makes it air tight. You have to be very careful handling it as the edges are like razors. Like you I use a slip of brown paper bag to burn out the oxygen without introducing any contaminants.

I like the charcoal method because I usually do a bunch of dies at one time and the mass of the crucible seems to slow the cooling process down enough to get it to work. I have a small kiln that came from a lab and works very well for treatment so far. I just acquired a larger one that was used for firing pottery and tiles but I have to rig up a temperature controller before I can use it.

I find the hobby has lead me in many directions to find answers but it has been a good learning experience. Though it seems the more I know the more questions I have. Thanks very much for the offer I may take you up on it.
Thanks, Diz

[mike ford]

Diz,
Again, Wonderful. Since everyone else is making suggestions, here are some more. Like you, I don't like to use oil hardening steel for general use. I built my house on top of my shop( my wife thinks it was the other way around),so things are more peaceful if I use water hardening steel. I just buy bars in certain useful sizes and use them, in addition to bolts as you do. One of the bar sizes I usually keep on hand is 7/8". To me it is easier to thread a piece of 7/8" stock than going through the process of annealing an old die. It's easier to get anything that is threaded to run true if you put it in a threading die, and chuck the die, using the tailstock to line it up. This works great when I shorten sizing dies. A jar of lanolin from the local drug store will lubricate an awful lot of bullets and also cases being swaged to smaller headsize. I don't harden too many things and they usually work well for the number of cases, bullets, etc. I make from them. For firing pins, I find water hardening steel is usually satisfactory, but of course harden them, and the punches used in forming Mauser base cases from 45-70. I do admit to using "casenit" to surface harden some things. I intend to study your procedures carefully and you will likely have some dumb questions from me.PS, Of course if I have to make a half reamer, I have to harden it. For that, I may use oil hardening steel, quenched outside, and drawn in my wife's oven( while she has gone somewhere).
Mike

[Diz]

Mike,

You make a good point about machining the thread but I get lazy sometimes and dies can make it easy as they are often just the right size at some point inside and have a nice taper especially for making push through dies. I had a piece of 7/8 threaded rod but used it. Lanolin is an excellent sizing lube as you mention and works wonders at keeping your skin soft too. The wife will appreciate that! I agree that "casenit" was about the best case hardening material around. I ran out awhile ago and bought some "cherry red" but I haven't had an occasion to use it. since I got into the bone charcoal thing I have been keeping with that.

I welcome any questions you have and hope I can answer to your and everyone's satisfaction.

Thanks, Diz