Dangers of Annealing improperly

[StevenD]

Folks,

Since the Broncos were a dismal failure this year and there are no football games I care deeply about, I thought I would peck this out on the keyboard to bore others as well as myself. Misery loves company, I guess.

Not to sound condescending, but I was reading a post that suggested annealing brass that may be "strain-hardened" due to shooting or whatever...

There are a number of reasons for annealing brass that I will leave for others, but for those that may not be aware, the head of the case (where the primer is and where the brand and caliber are stamped) is the weakest link in the containment of the explosion that occurs when the primer ignites. Chamber pressure limits of 60,000 psi or 45,000 cup's or whatever, at least as I have been told are not necessarily limited by the gun, but rather limited based on the strength of the brass at the case's head. This is why it is unsafe to exceed the SAAMI pressure limits. It's not because the rifle is so weak, but the brass can fail (and then the rifle, if it goes too far).

This area around the region of the head, as well as the head of the case proper must be kept from heating up excessively when annealing to prevent a loss of strength in the metal. For rimless cases which is what we mostly shoot for varmints, the head of the head of the case is not supported by the chamber, but extends out of the chamber far enough for the extractor to be able to grab and pull the case out of the chamber. If the case at this point is too soft the unsupported portion of the case head can split, sending the gases back toward you, or other problems that I won't go into here. Hence the importance of wearing shooting glasses and having a gun that has a gas shield on the bolt shroud to deflect the hot gases away from the shooter's face. (The shroud is most apparent on Mausers where it gets real wide at the fore-front of the shroud, closest to the chamber.)

Also, when the brass gets thin near the head of the case from shooting and resizing, the case can split at that location as well. However, this may not result in too much loss in pressure and you may not even realize a split has occurred until you look at the case.

So, before anyone delves into the process of annealing cases, be sure to read up on the subject. There are a number of good references from Hornady and others to explain the process. I just didn't want anyone out there heating up the entire case resulting in anyone being endanged.

Happy shooting.

[Hitman]

I was going to post this, but you did a fine job.

When I anneal, the brass is set in a pan of water to keep the case heads from overheating. I keep the water level within about 1/2" of the shoulder/body junction at a maximum. I refined my process to include rotation of the brass in an icewater bath while annealing. You would be surprised how fast the ice melts when annealing. About 25-30 pieces of brass and I Need more ice.

Thanks for your post.

[StevenD]

Thanks Hitman.

I was reading a post in a thread about the subject based on information from a metallurgist at an ammo factory. According to that info, the water process is not necessary for instantaneous cooling.

But as for me and my reloading bench, I like using water too because it ensures that I won't get distractd and heat up the heads as well as cool them quickly. I do have to wait awhile for them to dry though.

[keithcandler]

I put enough water in the pan to more than cover the brass.

[Don-LongRangeSupply.com]

Thanks Hitman.

I was reading a post in a thread about the subject based on information from a metallurgist at an ammo factory. According to that info, the water process is not necessary for instantaneous cooling.

But as for me and my reloading bench, I like using water too because it ensures that I won't get distractd and heat up the heads as well as cool them quickly. I do have to wait awhile for them to dry though.

Interesting.......everything I have read says that the cooling process is required to get the desired effect.

I think I will do some testing and see for myself. It would be nice to not have to get my 50 BMG cases wet. They take forever to dry.

[StevenD]

Interesting.......everything I have read says that the cooling process is required to get the desired effect.

I think I will do some testing and see for myself. It would be nice to not have to get my 50 BMG cases wet. They take forever to dry.

Don:

I should mention though that they do drop the cases into something that will cool them fairly quickly, like sand or something, just not water.

[Don-LongRangeSupply.com]

OK thanks.

I am thinking my case cleaner filled half way with sand would be a lot less messy than water for the 50 bmgs, and probably the others too.

[Markbo]

For reloading newbies like myself, can you tell me why and when you have to anneal? Is it only when resizing brass to a smaller cartridge, or changing to an AI or similar or do you do it on any/all brass that will be reloaded many times?

[StevenD]

For reloading newbies like myself, can you tell me why and when you have to anneal? Is it only when resizing brass to a smaller cartridge, or changing to an AI or similar or do you do it on any/all brass that will be reloaded many times?

There are a lot of differing opinions on this matter. Bench shooters that are trying to achieve a one hole take a different mind set on the matter. They may anneal brass in an attempt to achieve a certain amount of neck tension that they believe they need.

Simply put, for the most cartridges that are not wildcats, I would say that annealing is not really necessary unless you are experiencing problems with the case necks. Sometimes it is noticed during the first sizing or loading operation where some necks are splitting. (Incidentally, if nothing else, I clean up the mouth of new brass just a little to ease it going through sizer die, just to make the mouth and neck round. Anymore, it seems bulk brass has mouth & necks that are out-of-round and rough when brand new.) Sometimes it is when you fire the rounds. After just a couple of reloads for some magnums, it may be necessary to anneal the necks to get another few rounds out of them.

Sometimes it depends on the chamber. I had a 300 W.M. that did not like Federal brass for some reason and split the necks on the first shot. After annealing and taking some of the brittleness out of the necks and shoulders, I could get several re-loads out that brass before I had to anneal them again, which generally was not worth it to me. I did not shoot that gun so much that I couldn't afford to get new brass at that point. It was just a few shots a year for that rifle.

Anyway, I hope that confuses, I mean helps you a little.

[Markbo]

100% ;)