Stainless Steel Bullet Mould ????

[Southron Sanders]

Has anyone ever made a bullet mould out of Stainless Steel?

The problem with Meehanite (Iron) bullet moulds is that they have a tendency to rust when put away; unless you oil them .

Of course, before you can use them again, you have to remove all of the oil or your bullets will come out "wrinkled."

Seems to me, that stainless steel would be an IDEAL bullet mould material. SS would resist rust like brass and aluminum; be lighter than brass and much more durable than aluminum moulds.

Does anyone know exactly which Stainless Steel is the most "machinable," i.e., the "softest?" i.e, 303, 304 or 316 SS?

I have a lathe and would like to experiment by making a few SS moulds by the "lathe boring" method.

Any Comments? Your advice and insights would be most Welcome!

[HeavyMetal]

I think what your going to have a tuff time with is finish!

300 series stainless won't rust but it can be a pain to get the same type finish you can get in a mehanite or aluminum mold. Gun makers found this out years ago!

That's why they all use 400 series stainless to make guns it's easy on tooling and not as "gummy' during the cuting.

I'm interested in how this turns out but I think you won't be able to polish the stainless enough to get the boolits to release from the mold.

However nassity is the mother of invention! You may come up with a new way to polish stainless which is very labor intensive.

Good luck.

[xr650]

303 would be a good place to start. 304 and 316 are tougher to machine.
Will stainless take the repeated heat/cool cycles without warpage?

[jhrosier]

....
The problem with Meehanite (Iron) bullet moulds is that they have a tendency to rust when put away; unless you oil them ....

Put your moulds in an ammo can with a piece of vapor barrier paper and they will never rust.
Mine have been stored this way for more than three decades with no problem.
I do not oil them before storage or clean them before use.

A fifty cal can will hold the four cavity Lyman moulds, with handles attached.

Jack

[floodgate]

Back in the early 1920s Belding & Mull made mould blocks in pure nickel as well as iron. They worked well and never rusted, but the nickel tended to wear the tooling very fast, and they had a lot of rejects. As a result they charged about twice the price of their iron moulds for them, and they didn't sell well, so were soon dropped. Early B&M moulds were marked "IRON" or "NICKEL" to tell them apart, as they looked and hefted about the same (nickel is even slightly magnetic, so a magnet test didn't always show the difference). I have only seen or heard of a couple of these, so if you ever run across a B&M mould with the "NICKEL" stamp on it, I wanna hear about it!.

Seriously, with modern carbide, ceramic, etc., cutting tools, nickel might be practical again.

floodgate

[mooman76]

I'm thinking a high grade of aluminum, like aircraft aluminum would work better but I'm not a machinest so I don't really know.

[Buckshot]

I'm thinking a high grade of aluminum, like aircraft aluminum would work better but I'm not a machinest so I don't really know.

...............The main issue with most any aluminum is that casting temps can run very close to annealing temps.

...............Buckshot

[nemo]

it was said when alun. came out they would warp too much.Lee proved them wrong.Alum melts at 1100 and casts at 1150 to 1175. sound Filmier? Lead 620 cast 680 about lead alloys cast around 650 to 680 ,antimony 1100 lead 620 tin 450 ??? acft.alum is a good choice 2024 t3 works good on a lathe bore mold. Most warping
is done in draft mold not opened or on a non even surface a lot are thru
lazyness or not knowing . all you can do Mr.Buckshot is try Good Luck. Let us know what you find out.
nemo

[madcaster]

Bronze moulds work great too!

[44man]

Stainless steel DOES NOT TRANSFER HEAT well. It will give you all kinds of hot and cold spot troubles. That can also cause all kinds of dimensional problems.
That is why good cooking pots have aluminum or copper bottoms fused to the stainless.

[Old Ironsights]

I really considered a Brass mould when I had a single cavity cut at Mt Moulds... Chickened out though and got Aluminium.

OTOH, I have never had a lick of trouble with my Lymans either...

[smokemjoe]

I worked in a nuke shop using 316 and 415, Both are nice to work with if you got the right tooling ground by the tool grinders. use oil for cooling, If you could soften S.S. and then heat treat by freezing down under 180 Deg. and bringing it back. It would be interesting to see how a mould would cast. Joe

[Southron Sanders]

I am just a home shop machinist, so doing any exotic things are beyone my scope.

I guess that the "heat transfer" issue might be the deciding one about SS bullet moulds.

I have owned and used many aluminum bullet moulds (made by both Rapine and Lee) and maybe I am just too "ham handed," but they don't seem to last very long for me compared to iron and brass moulds.

I can understany why mould makers LOVE aluminum moulds. The aluminum is not only less costly compared to brass and other metals, but also machines beautifully-which accounts for long tool life.

My son lathe bored a brass .515 bullet mould for his Smith Carbine, and the mould (outside of being on the somewhat heavy side) is fabulous. Heats quickly, bullets pop out with no problem and the mould never rusts or gives any other problems. He made the mould out of 360 Brass.

I had never thought of the Nickel moulds. That is an interesting idea.

[bruce drake]

Has anyone ever blued their molds to keep them from rusting?

Just curious.

Bruce

[Red River Rick]

it was said when alun. came out they would warp too much.Lee proved them wrong.Alum melts at 1100 and casts at 1150 to 1175. sound Filmier? Lead 620 cast 680 about lead alloys cast around 650 to 680 ,antimony 1100 lead 620 tin 450 ??? acft.alum is a good choice 2024 t3 works good on a lathe bore mold. Most warping
is done in draft mold not opened or on a non even surface a lot are thru
lazyness or not knowing . all you can do Mr.Buckshot is try Good Luck. Let us know what you find out.
nemo


Lee has proved nothing by making their moulds out of aluminum other than cost reductions. If you look closely at Lee moulds, you can clearly see that their blocks are cut from lengths of extuded aluminum bar stock (made to their specs). Which, in turn, reduces manufacturing costs.

Cost is the only factor why Lee uses aluminum, and the quality, well that's another issue. If you read a lot of the posts on this forum, regarding Lee moulds, you'll notice that "Quality" is somewhat a bit of an issue almost all of the time. Yet, all the high end moulds made from iron and or brass never seem to have the problems that Lee moulds have. You get what you pay for.

Buckshot is correct about annealing temperatures and aluminum moulds, especially if one of the "Harder" grades of aluminum alloys are going to be used.

Stainless steel would be nice, but the machinablity tends to hamper it's use on a commercial scale. You could probably cut 5 times the amount of moulds made from Iron (Duara-Bar 65-45-12) as you could from stainless using the same tooling. Unless your machining moulds out of 303 MX Stainless (free machining), Iron or Brass will still be better in the long run.

RRR

[badgeredd]

I am just a home shop machinist, so doing any exotic things are beyone my scope. As a plastic injection mold-maker, I understand what you are saying about exotic, but if you have a heat treat facility in your area, the cost isn't usually too bad to have heat treat done.

I guess that the "heat transfer" issue might be the deciding one about SS bullet moulds. A couple of stainless steels that may work for a mold is 416 and 420. Both need to be heat treated to bring them up to 48 to 52 Rc hardness to make them as rust resistant as possible. Both are used in molds for plastics where heat transfer is a issue that has to be considered. IMO they would work in boolit mold. Both are fairly decent to machine but neither is totally rust proof.

I can understany why mould makers LOVE aluminum moulds. The aluminum is not only less costly compared to brass and other metals, but also machines beautifully-which accounts for long tool life. You bet your bippie! For prototype tooling it is great, especially 7075 T6. The down side is it IS aluminum and subject to damage easier than almost any steel.

My son lathe bored a brass .515 bullet mould for his Smith Carbine, and the mould (outside of being on the somewhat heavy side) is fabulous. Heats quickly, bullets pop out with no problem and the mould never rusts or gives any other problems. He made the mould out of 360 Brass. Some bronzes have high aluminum and/or tin content and are a pain to machine, the tool must be exceptionally sharp or it will "slide" over the surface and the dig in or gouge. I'm not really that familiar with brass alloys though.

I had never thought of the Nickel moulds. That is an interesting idea.A high nickel steel may be good too, but I suspect you'd have a machining issue with it too. If I remember correctly, there were some actions made for Springfields that were high nickel content, but it seems to me there was a problem with some of the heat treat procedures initially. THIS I could be all wet about though.

Just my $.02 on the mold thing.

I just remmbered there are a couple fellows on the forum that are mechanical engineers and they should be a great deal of help with metal selections other than the norm for boolit molds.

[HORNET]

I'll agree on the heat transfer problems with the stainless. Stainless steels , even the 416 & 420, have much lower thermal conductivity than even the tool steels like H-13 & D-2. If you want something that machines well and really moves heat, look at some of the aluminum bronzes. AMPCO makes some that are as good, if not better than, beryllium copper without the health hazards. APMCO 940 conducts heat really well.

[warf73]

Invar, also known generically 64FeNi, is a nickel steel alloy notable for its uniquely low coefficient of thermal expansion, this material is used for making all of our tools were I work. It can be taken to a mirror finish without much issue. But it’s very costly the Current price is around $13 a pound. It machines like most mild steel.
This would be great material to make molds out of if a guy can find scrap pieces of it at a Yard store or a metal recycling center.

[longbow]

I'll add a comment about heat transfer (or lack thereof) of stainless moulds.

I have a stainless pushout mould I made first for .44 mag paper patching then bored it out to make 12 ga. slugs. It is a piece of surface ground stainless shafting. I don't know the grade but much harder and tougher than 316.

It does not transfer heat well so the only way I can keep up a reasonable casting rate is to dip it in water regularly. A quick dip of the bottom helps cool it enough otherwise casting is very slow.

Longbow

[mfraser264]

My place of work, a foundry pours stainless steel weekly. We pour 304 & 316 (CF3 & 8M)and also 174PH. The hear treat is simple after casting, normalize @1950 for 1 hour and water quench. You do not get a hardened material as you do with carbon steel, lack of carbon limits the heat treat properties, we go through this with customers all the time. We also machine the SS and it is not easy unless with the correct tooling. As compared to 174PH, it machines harder but is more hard than 316.

I'll comment on another material in another posting.

Markus

[Bret4207]

I keep my moulds in a dead freezer in my barn here in the humid north east with a dessicant box from Brownells. ZERO rust problems and there is no oil on any of my moulds. You're seeking an answer for a problem thats already been fixed.