Searching for some steel.

[Erwan]

Hi ,
This is my first intervention on this forum, be cool in your answer(s) and language: I'm not American, and the time I was working for the Army at Wiesbaden (Germany) is far behind me (1969), and the school is largely more behind.
So If you can understand what I'll ask you is this: does somebody tell me what kind of steel could be good to build a bullet mold for long range shooting?
That steel must be resilient and have a small coefficient of expansion. The smallest coefficient would be (I think) the best for machining on a lathe, and be close to the final right bullet size at 400°F when putting the lead in. To the smallest coefficient of expansion from 0 to 400°F, do somebody tell me what kind of steel could be for this?
I anybody doesn't know, tell me too: I still continue my research.
That all people here have a pretty good day.
Erwan.

 

[blvckisking]

Tool steels like A2 or D2 are tough, machine well, and hold up to heat. H13 is another popular choice because it handles repeated heating and has a pretty low thermal expansion, so your bullets stay consistent

 

[favorit0]

H13 is especially nice for repeated heating, it has decent toughness, and a relatively low thermal expansion

 

[gl0vetr0tt3r]

Hi ,
This is my first intervention on this forum, be cool in your answer(s) and language: I'm not American, and the time I was working for the Army at Wiesbaden (Germany) is far behind me (1969), and the school is largely more behind.
So If you can understand what I'll ask you is this: does somebody tell me what kind of steel could be good to build a bullet mold for long range shooting?
That steel must be resilient and have a small coefficient of expansion. The smallest coefficient would be (I think) the best for machining on a lathe, and be close to the final right bullet size at 400°F when putting the lead in. To the smallest coefficient of expansion from 0 to 400°F, do somebody tell me what kind of steel could be for this?
I anybody doesn't know, tell me too: I still continue my research.
That all people here have a pretty good day.
Erwan.

Hey, welcome to the forum! For the kind of project you're describing, a great option that many custom mold makers use is 4140 steel. It's a chrome-moly alloy steel known for its toughness, excellent machinability, and good dimensional stability when heat-treated. It's a solid balance of all the properties you're looking for! I'd lean towards this but another option is O1 tool steel. It's an oil-hardening steel that's very stable after heat-treating and can hold a very fine edge.

 

[t_bone]

hi @Erwan, many high end custom mold makers (like the ones who machine 400+ long range bullet molds) often go with high carbon tool steels, but for extreme stability and excellent machinability, look into AISI O1. It has a good balance of properties and is often chosen because it is oil hardening with low distortion during heat treatment

 

[Billinthedesert]

Good luck, Erwan. RCBS apparently uses cast iron for molds, while Lyman uses leaded steel. Accurate uses ductile cast iron as well as easy-machining 360 Brass, or C36000.
Lead melts at 621 degrees F.
Love your sig line from Calvin and Hobbes.

 

[Greg Looney]

Hi ,
This is my first intervention on this forum, be cool in your answer(s) and language: I'm not American, and the time I was working for the Army at Wiesbaden (Germany) is far behind me (1969), and the school is largely more behind.
So If you can understand what I'll ask you is this: does somebody tell me what kind of steel could be good to build a bullet mold for long range shooting?
That steel must be resilient and have a small coefficient of expansion. The smallest coefficient would be (I think) the best for machining on a lathe, and be close to the final right bullet size at 400°F when putting the lead in. To the smallest coefficient of expansion from 0 to 400°F, do somebody tell me what kind of steel could be for this?
I anybody doesn't know, tell me too: I still continue my research.
That all people here have a pretty good day.
Erwan.

https://accuratemolds.com/ This company has blank mold blocks for sale. In addition, they will make custom mold for you in any configuration.

 

[FPDoc]

Hi ,
This is my first intervention on this forum, be cool in your answer(s) and language: I'm not American, and the time I was working for the Army at Wiesbaden (Germany) is far behind me (1969), and the school is largely more behind.
So If you can understand what I'll ask you is this: does somebody tell me what kind of steel could be good to build a bullet mold for long range shooting?
That steel must be resilient and have a small coefficient of expansion. The smallest coefficient would be (I think) the best for machining on a lathe, and be close to the final right bullet size at 400°F when putting the lead in. To the smallest coefficient of expansion from 0 to 400°F, do somebody tell me what kind of steel could be for this?
I anybody doesn't know, tell me too: I still continue my research.
That all people here have a pretty good day.
Erwan.

NOE brand bullet molds are made from 2024 aluminum I believe ànd have a very good reputation regarding quality. Many bullet mold manufacturers will sell blank blocks so you can machine your own design if you wish.