Do I need to anneal?

[esshup]

I'm puzzled, and need some input from a more experienced reloader than myself.

Case .338 Lapua necked down and fireformed to 7mm AM by Kirby's Dad.

This is the first full pressure load fired in this particular case. After firing, the case is cracked parallel to the case length on the shoulder, and the neck/shoulder junction shows smaller cracks around the case, again parallel to the case.

This case is part of a batch that was loaded by Kirby. Other rounds fired from the same loading batch did not exhibit this problem. The only difference is it is a year later; the ambient temp is 5°F higher and the altitude is roughly 3500 feet lower.

This is the first case that has exhibited this problem, from roughly 50 fired. I have two different lot numbers of cases, for a total of 200 cases. The remainder of the 200 cases have not been loaded for their first full pressure firing yet.

Is this something that I shouldn't worry about and consider it normal, or should I take steps to do something different?

Here's the load data:
Lapua brass, first full pressure firing.
175g SMK
110g WC872
Fed-215 primer

 

[Buffalobob]

What Kirby used to advise was to anneal after the first full power firing. I do not remember or else do not know how they fire form the brass other than he made some kind of stubby barreled chamber.

The question would be if it is full power or just cornmeal. However, I would think that if the brass needed to be annealed before the customer fired it that he would just use an automatic rotary machine to do that before delivering it to the customer. That's just my opinion and not necessarily the facts

 

[esshup]

Thanks Bob.

I believe his dad uses cornmeal in something other than a full on gun. The fireformed brass has a small radius on the shoulder that becomes a sharp shoulder after the first full power firing. This was a piece of brass that still had the "soft" shoulder radius. I'm trying to keep the 2 lots of brass separate, and keep the same number of firings on them. i.e. fire the first 100 once then load the 2nd 100.

 

[Buffalobob]

Well, you should not need to anneal until after you have fired it one time.

One thing you might just check is to take a bent paperclip and a strong lamp or flash light and see if there is any cornmeal stuck inside the cases either on the shoulder or in the neck. It happens with me frequently so I inspect each of my cases after I cornmeal form them.

 

[esshup]

Thanks Bob. I checked all the cases and they have no residue in them. re: The case that cracked; it cracked on the first full power firing.

I'll be looking at your method of annealing, I don't think I need to buy one of the annealing machines, although it would be nice to have.

 

[Pdvdh]

If it split upon firing, then I would say you should anneal the case necks or risk losing more brass. You could fire another one or two and see if you get another case neck shoulder area split/crack. If so, annealing will solve this.

I has this happen when resizing and fire-forming RWS 404 Jeffery brass to 338 Imperial Magnum/Edge. Lost two of the first four casing just during fire-forming. Annealed the rest and no more splits.

 

[esshup]

This is the first one out of about 50 fired that split, but I don't want to lose any more than necessary. Who's to say that if I don't anneal them, then I'd have 10% go with the next firing?

 

[Buffalobob]

It won't hurt anything to do a slight annealing, but you should be careful to not over do it.

I have pretty much started annealing 7AM brass after every firing.

 

[esshup]

I have pretty much started annealing 7AM brass after every firing.

That's good to know.

 

[Pdvdh]

My annealing time in a propane torch with the hot focused tip of the flame measuring 3/4" long, and focused at the junction of the neck and shoulder, is 5.5 seconds. This is with the case spinning in a cordless drill for even exposure to the flame. I do this with a large second hand clock in the background, to time each casing for relatively uniform annealing of each case, and to prevent over-cooking the brass. Then I plop the case into cold water to prevent the heat from moving down toward the case head. De-prime all cases before doing this annealing.