08 May 2017

The Riddle Of Steels

In talking about what constitutes barrel steel it's important to keep in mind that the chemical composition is actually a very small part of the puzzle about how good the material is for your purpose.

The mechanical properties matter a lot more to the user, the alloy is simply how the steel maker achieves the goal.

When you look at how the composition between Ord4150, Ord4150(resulfurized) and CMV differ, you have to bear in mind that the DoD doesn't distinguish between them.  To the milspec, these are simply MIL-B-11595E compliant barrel steels.

There might be a better steel for a barrel, but the nature of milspec means you're in trouble for using it on a gun you're selling to the DoD.

The mechanical properties of the milspec barrel steels, by the way, stresses durability in the face of extremes in environmental temperatures with very high barrel temperatures.  You know, the kind of conditions that even the gamers don't encounter much even with their high round counts.

A real engineer could probably break it down better, but always keep in the back of your head that 4140 has a higher yield strength than 4150, yet is scorned...

Make sure you specify the material that does what you want and have someone who knows what they're doing help.  Otherwise, you're just on the fashion show runway.

2 comments:

  1. In talking about what constitutes barrel steel it's important to keep in mind that the chemical composition is actually a very small part of the puzzle about how good the material is for your purpose. Word. I took two elective classes in Materials Science in the engineering school years. You spend literally a full quarter studying the phase diagrams for steels, with all the implications of heat treating, annealing, forming martensite, austenite, oil cooling, water cooling, air cooling and more that I can't recall.

    Steel is incredibly complex stuff.

    You'll sometimes run across guys who talk about a scifi concept called "gray goo". The idea that we'll somehow create nanites - programmable nano assemblers of some sort - that produce steel by picking atoms of iron and the other constituents out of ore and create steel for us. It shows stunning ignorance of the complex processes used to turn those recipes into steels that behave the way we want or stunning ignorance of the details of the microstructure of steel.

    Do the milspecs specify how the barrel is formed? A barrel that's hammer forged cold is going to behave differently than one that's cold-rifled with a cutter and lots of lubricants to keep the temperature down or one that's done when the barrel is still red hot.

    ReplyDelete
  2. Some materials are spec'd for availability also. We switched steels at work from an H-10 Modified to 1.2367 just because it's easier to get. I thought I've heard similar about some gun parts, Carpenter 158 maybe?

    ReplyDelete

Try to remember you are a guest here when you comment. Inappropriate comments will be deleted without mention. Amnesty period is expired.