Annealing Process

  • It is very clear that the brass cartridge cases must be annealled in order the upper part to be soft and not brittle while the rest of the brass cartridge case must remain strong and not affected by the annealing process. — My question is: Do the steel or CWS made cartridge cases have to be annealled too before loading??? Thanks in advance for any help, Liviu 07/16/07


What is the “ANNEALING PROCESS”? I love fabrication knowlege :-)


The annealing process is, simply and non-scientifically put, a heating process by which the neck of a case, in the instance of bottle-necked cases down to a point below the shoulder, is softened to allow more elasticity for bullet seating, obturation, etc., to avoid cracking of the necks. Most militaries require the discoloration left by the process remain on the case as proof of annealing. On most civilian ammo, it is polished off as it is felt that the discoloration makes the ammo look less desireable to retail customers, most of whom do not know why the discoloration is there, and think it is some form of corrosion.

I know that the process involves heating the case mouth to a certain color which people experienced in this process can even identify by eye, and then cooling the case by various means. On an all-too-short visit to BELL Lab when it was near Chicago, I watched this process. It was interesting, but not being scientifically inclined, I cannot quote temperatures, the facts of the cooling process, etc.

The entire case is not annealed as that would make the base of the cartridge too soft for the function it performs.

I used to make 7.62 x 39mm out of Norma 6.5 Mannlicher-Schoenauer brass (yes, I regret ruining 300 or so of those now hard-to-find cases to make a cartridge that is now 15 cents apiece, but at the time, there was NO ammunition available for my SKS Carbine and Valmet Model 62). This involved shortening the case past the annealing. I did not re-anneal them as I had no idea how, nor the equipment to do it with. The cartridges were perfectly safe to fire, and were very accurate (much more so than any combloc military load, and even than Lapua ammo, which was far better than any other factory ammo I ever shot in this caliber). However, predictably, after about the third or fourth loading, the case necks pretty consistently split. A very expensive proposition. I used a 150 grain .303 British bullet, by the way, as there were no bullets of the weight range of 120 to 125 grains available at that time in the proper dimeter. Very accurate, but with a trajectory like a rainbow, as there was also no loading data so I was winging it.

Note that I have given no loading data here, which is irrelevent to the question, and not allowed on this Forum.


Steel cases ?

  • @ John Moss: Many thanks for your reply. When the temperature of 660-665 degrees Fahrenheit reaches the brass area at the cartridge case mouth, the surface becomes light blue, the annealing process is done but the heated brass cartridge case must be dropped into the water. My initial question still remains: — Do the cartridge cases made of STEEL or CWS [copper washed steel] have to be annealled or not before loading??? I know that the steel cartridge cases are not reused and reloaded. Steel is different [if compared with brass] because if it is cooled rapidly after heating, it becomes harder. NOTE: Normally the brass used for cartridge cases is made of 70% copper and 30% zinc. Liviu 07/16/07


Steel case? I haven’t a clue.



I cannot say positively that steel cases are not annealed during the forming process, but I have not seen any reference indicating that they are and I don’t believe it is necessary to do so.

Brass has many charcteristics that make it the perfect material for cartridge cases. One of these, different from steel, is that brass hardens when worked. During the drawing or extruding process in making a case, it may go through as many as 4 or 5 seperate annealings to keep them soft enough for the next step. The final body anneal is carefully controlled to give the case walls a tough structure while keeping the case head hard. After the necking down steps are completed the mouth, neck and part of the shoulder are annealed.

Many shooters will anneal the case necks after several reloads and it is not a complicated process. High heat is all that is necessary and the cases may be quenched in water or allowed to air cool. Unlike steel, brass does not harden when heated and quenched or soften if heated and air cooled.

Since steel does not work harden to the extent of brass I cannot see where annealing during the manufacture of a cartridge case would be necessary. But, as I said, I am not positive.



While I can’t address the question regarding the need to anneal steel cases, I believe that steel needs only to be heated to the proper temperature and then allowed to cool on its own in order to anneal it, unlike brass that has already been pointed out must be rapidly cooled to complete the annealing process.


I recall seeing the process being done with the cases in a water bath with a gang of gas fired burners heating the noted discolored shoulder and neck of the case. I do not recall if they were in some sort of conveyor or a batch system. I’m betting conveyor. The added polishing for commercial sales asthetics equates to “painting” oranges orange. Oh well.


Slick Rick - while I agree with you completely in principle about "painting oranges orange, the reality of the retail market is that most people who buy ammunition are not ammunition experts, but rather the casual shooter (most serious shooters reload) buying ammo for his once a year hunting trip, his once a year trip to the range, or for his home defense gun. When they see anything but shiny brass, they don’t want the ammunition. This is also one of the reasons that commercial ammunition is not normally dated on the headstamp, and that dates in lot numbers on boxes are coded. Tell the same customer that, to save money, buys surplus military ammo 30 years old without thinking about the age from the date on the heradstamp that the 20.00 box of Winchester pistol ammo he is buying off of your shelf is five years old, and he’ll look you in the eye and say I don’t want “old stuff.” Again, people who don’t know what annealing is and why it is done think the annealing on cartridge cases is some sort of corrosion or


What John says is true. Shooters in general are very finiky when it comes to the looks of their ammunition. In fact, most bullet and case makers will sell their “blemished” items at bulk discount rates rather than try to convince shooters that a blemish is nothing but discoloration and has nothing to do with accuracy.

However, there is a trend today toward what are known as the premium brass cases - those made by LAPUA, ALEX A, RAUG, etc. They leave the anneal colors intact and it gives them sort of a custom, sleek, expensive look that some shooters go for. It’s a big selling point and I would not be surprised to see some of the major ammunition makers picking up on it.



Maybe there’s hope for the average shooter after all. I have been retired for almost seven years. Perhaps the average shooter is getting better educated in the subject of arms and ammunition. I hope so. No need to be an a so-called expert, but most of those that shoot at public ranges, anyway, could use a little more knowledge of the guns and ammunition that they are shooting. But then, when I was working, we were blessed with a lot of customers that really knew their stuff, including even two pre-teen youngsters, one of which was so adult and so knowledgeable on firearms I almost felt sorry for him - it seemed like he missed a big part of a normal childhood. His dad admitted to me that he knew more about guns and ammo than the dad, a man with a very respectable grasp of firearms knowledge himself. I kind of think the young man knew more about it than the man serving him - me! It wasn’t all grim and ignorance. We had a whole bunch of really good customers - good shooters, knowledgeable collectors, expert reloaders, etc. It made the job bearable right up to the end, despite all the government interference in our profession.

  • I don’t think that 5% of the shooters of today take a look at the headstamp markings before to load the ammo into their weapons … and even if they bother to see the headstamp markings, how much do they understand [especially when the ammo is old surplus]??? — A few days ago at a local “Gun Shop” the owner had no idea where the ammo had been manufactured if on the packing box was not printed “Made in …” He had for sale a nice looking .303 British No1MkIII bolt action rifle but he had no idea when and where the weapon had been manufactured, though it was marked “Lithgow” and “1941”. No more comments. Liviu 07/17/07


My experience is that your 5% is generous.

  • @ CSAEOD: I’ve always been a generous person … Liviu 07/17/07


I believe you.

Your work in filling out holes in the story of Romanian weapons and ammo has been very generous.

Good luck with it !


Hard for me to get excited about shotshells BUT those Romanian ones which you have in the current JOURNAL are interesting.

  • @ CSAEOD: Unfortunately there are still some question marks about the Romanian ammo and Romanian headstamps, especially the old rimmed 6.5X53R cartridges manufactured before WW1. I hope that in the future answers will be found. — I hate now to repeat myself but the QUESTION of this topic still remains unanswered: “Do the steel or CWS made cartridge cases have to be annealled or not???” Liviu 07/17/07


The answer is coming soon.


The answer according to Col. Frank Hackley - last Commander of Frankford Arsenal.

John: Yes, steel cases are normally heat-treated between key forming operations to remove any stresses set-up during the manufacturing process. During WWII a number of case suppliers attempted to make steel cases using the brass process, but most were not successful. Modern steel cases can also be made using cold-worked and extruded techniques, which reduces or in some cases eliminates the need for heat treatment.