• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

Brass Hardness Question

Basic user

Private
Supporter
Full Member
Minuteman
  • Oct 11, 2013
    234
    56
    Quick question; Glen Zedikers book "Top Grade Ammo", when describing casings, said "harder is better". He said Winchester, Nosler and LC brass is hard, and the others are soft, especially Lapuas. First, I'm understanding that the key attraction to Lapua's inordinately expensive brass is it's consistency. But it's too soft? So out of alll the brass makers out there, we can only get soft and consistent or hard and inconsistent? Because all the top guys use Lapua, is consistency better than hardness?
    Secondly, I hear the more you work brass the harder it gets; does Lapua get harder and harder over time? Or does annealing fix that? And if it does, why do we want to fix soft brass? I thought we wanted it hard like Glen Zediker does.

    Anyone have any insight to this?
     
    • Like
    Reactions: simonp
    Does he explain why "harder is better"?

    My first consideration with brass is consistency. What shoots the best? Among available brass, Lapua is tops here.

    Brass life and availability, by a large margin, are second and third considerations, in no particular order. I've found Lapua to rate positively in both of these categories as well - 10+ firings is not unusual unless I'm abusing my brass. Hardness by itself doesn't enter the equation.

    If I can get Lapua brass, I get Lapua brass.

    The only brass I consider superior is RWS, but it's hard to find and has limited caliber choices - but a lot of different ones than Lapua, which is nice if you're shooting something a little different.
     
    @Scimitar has it right. I have used LC, Winchester and Lapua in both 223 and 308. Base hardness is going to help handle higher pressure loads. It doesn't have any quantitative effect on accuracy beyond the the higher pressure (velocity) versus brass life issue. The issue with Lapua is one I have not heard of. It may well be that it is softer but I can't say I've experienced issues with it. Certainly LC is harder based on my experience.
     
    The comment your quoting from his book, like mentioned above is not really giving the whole story... or much of the story at all. "Harder is better" makes absolutely no sense.

    All brass cases have a hardness gradient (and thickness gradient) - softest at the neck and hardest at the base/case head. Each manufacturer will have their own gradient based on their brass material properties and manufacturing methods. I've done failure analysis for some law enforcement guns, and one of the first things was to have samples of the issued ammunition disassembled and hardness tested, and compared against multiple other well known brands. They were all different across the brands, but fairly close to each other along the gradient.

    Brass cartridge cases are designed and measured by percent of ultimate strain - every time the brass cartridge case is used in a live fire event (generally once except in the case of reloading), the case will expand, and subsequently make contact with the chamber walls in a radial fashion (and longitudinally until the case head contacts the cartridge seat/bolt face), at which point the chamber itself expands an exceedingly small amount. Skipping a few steps, once the max pressure has been met, and the projectile is released from the case neck and travels down the bore until it uncorks, the reduction in pressure allows for the elastic recovery of both the chamber, and the elastic portion of the brass case deflection (the case then shrinks back down a very small amount).

    Lapua has built its reputation on making high quality brass cartridge cases, so to say they're soft really isn't correct. All brass cartridges cases are soft, and all are hard, the specific material makeup and the methods with which they're manufactured, along with final case annealing/prep by the manufacturer will dictate exactly how hard and soft they are.

    Hope the above helps you understand a little bit more about what's going on with brass cases, and why the quote from the book isn't particularly accurate.
     
    Cases that will withstand higher pressure without case head expansion is what he was probably getting at.
     
    Every piece of Nosler brass I had seemed soft to me. Maybe it was the 22 nosler was just absolutely brutal on it, but it didn’t last long.
     
    He said Winchester, Nosler and LC brass is hard, and the others are soft, especially Lapuas.
    Those are facts (at times), but they need clarification and context. Only the LC is held to known specs, the commercial outfits do as they want and at times they have made changes.

    Commercial brass and Mil-Spec brass can be the same and they can also be different in terms of properties and heat treatment that affects hardness. There are times when commercial outfits may or may not follow the Mil-Specs.

    Brass under contract to the DoD follows a Mil-Spec. That specification is typically designed to serve all the weapons that use the cartridge, which includes automatic and powered actions, not just bolt guns. Brass that can work perfectly well in a bolt gun, can cause issues in automatics, especially with respect to the rims and heads.

    Glenn was discussing reloading in general, but was often focused on semi-auto Service Rifles when he made those kinds of comments.

    He was not wrong even in general, but it is far less important in a bolt rig than it is with an automatic.

    Mil-Spec brass intended for an AR is harder at the head/rim than commercial brass on average. Commercial brass folks can do what they want and at times their hardness can be the same as Mil-Spec but often brass like Lapua is softer at the rim/head.

    If you flip through a web site like Starline, you might notice they sell two types of 223/556 brass, and the difference is the hardness of the head/rim area. Here is a plot of the requirement for a typical 5.56 case intended for the old M855 spec.

    Notice that there isn't a single hardness value, there is a hardness tolerance by zone. In this example, the head/rim area is roughly 175 while the neck is roughly 103. It may or may not sound like a big difference to you, but it is.

    Keep in mind, we use hardness as a proxy value for other material properties. In other words, it isn't really specifically the hardness we are all that concerned about. We use hardness because the other properties like tensile and yield strength that are coupled to the hardness are so much more difficult to measure, thus we use hardness in production control because it is easy to test. The main point is, when that hardness is right, the modulus, yield and tensile strength are also going to follow.

    1688747241941.png

    Secondly, I hear the more you work brass the harder it gets; does Lapua get harder and harder over time? Or does annealing fix that? And if it does, why do we want to fix soft brass? I thought we wanted it hard like Glen Zediker does.
    Cartridge brass has a simple crystal structure that work hardens under pressure and strain. We don't think of cartridge brass as one value, because we want different properties in the rims, heads, and bodies, than we do in the necks.

    If the brass was as hard in the neck as it was in the head, the neck tension would be difficult to control and have more potential for splitting in storage. If the brass was as soft in the head as it is in the necks, there would be gas leaks around the primer and there would also be potential for the rim to get bent on extraction.

    You don't need the engineering details to imagine how lucky we are as reloaders that brass is so magical or how difficult it is to substitute it with other materials.

    If you think of the expansion/contraction you perform on the necks with your dies when you size them, that plastic strain (cold working) hardens the brass.

    In the same way, when you fire the cartridge a 55 KSI pressure is also work hardening all the brass, including the body and head. It is just that most folks don't have a hardness tester or metallurgical lab to notice the tiny changes in the body and heads.

    Heads do harden but much less than the necks due to their being constrained by the chamber dimensions. Limiting the body and head strain keeps these parts of the case at a much lower cold working change level than the neck zone, so the change per cycle in heads is much smaller compared to necks.

    On the other hand, think of how large the chamber diameter is over the neck. It certainly allows the neck to release the bullet and then some, but the body is held much tighter, so because the strain is lower on the head but much higher at the neck the work hardening per cycle is very different.

    A typical SAAMI chamber allows factors more expansion over the neck compared to the body. If the body and head are allowed to expand like the neck, they would increase hardness and also cause lots of trouble, clickers, primer leaks, cracks, etc..

    Enough metallurgy and engineering... Glen was correct, Lapua is great brass but will not do as well as LC in an AR Service Rifle over several cycles for example. Service Rifles are just hard on brass (and typically only get four or five good cycles anyway). That difference isn't worth talking about if the context is bolt rifles where it would be hard to do better than Lapua.

    I will also mention, when specification committees are working for the DoD, they don't really worry about reloaders. We assume the brass is gone but we make sure it is reliable for purpose. When commercial outfits design their heat treat specifications, maybe they think about reloaders and maybe they don't...

    Some commercial names force us to track which version of their brass we are considering because they make some that is close to LC/Mil-Spec, but also some that is not worth reloading. As an example, there have been versions of Federal that mimic Mil brass but had very thin webs that would give up the primer pocket on the first cycle, while at the same time they made other versions that were LC clones.

    It is purely luck, that the things done to make the Mil brass reliable, happened to be pretty good for reloaders.

    My advice is not to agonize over the engineering and specification details. The concept Glen was trying to communicate was correct for a Service Rifle user. They can also use Lapua, but they should expect it not to last as long as Lake City. That is like saying three cycles instead of four, or four cycles instead of five. In some gas guns, you can bend a Lapua rim in one cycle. That is not always the fault of the brass, and not as important as the concept of consistency.

    At the time he wrote those comments, Winchester was putting out brass that was the equal of Lake City in the head zone in terms of heat treatment. Since then, we have seen it drift in and out. In the commercial world, there are no guarantees they are holding to Mil-Specs, (nor do they need to).

    The bottom line is to start and stay with the best brass you can afford/find and pay attention to the amount and consistency of the cold work you are doing in prep. It is possible to put off annealing and adjust your sizing process with cycles and do just fine.

    The hardness of the neck is certainly important to the tune/recipe but is only one factor of many. As a beginner, keep in mind that many recipes have a wide zone where the hardness value of the neck will work. The "stiffness" and yield strength of the necks will change with cycles if you don't anneal, but that is not as important as keeping them consistent in friction and workmanship. The hoop pressure the necks put on the bullet is often discussed, but the friction is not mentioned as often. Keeping the chamfer and friction in the workmanship is just as important since the release force is the product of both the mechanical properties and dimensions of the neck multiplied by the friction coefficient. Not managing the friction or chamfer will be just as bad or worse than if you don't keep the neck hardness consistent.

    You will have to learn to shoot, read wind, reload, and tune for a while before you can shoot the difference in these details so I would focus on the concept of keeping your brass consistent within and between batches. The higher the quality of the brass you start with, the easier that task will be, but you could get to Mid Range High Master with average brass and no annealing before you worry about details like we have been discussing. YMMV

    We lost Glen too young. He was a husband and a father, a good shot, and a great guy. Memory Eternal.