Cracked .303 Brit case neck.

I sat down to reload a box of PPU .303 Brit and saw something new, at least for me. Five of the cases out of 20 had cracked necks and had to be scrapped. I've been reloading for a few years and these cases have been reloaded many times. I only resize the necks of the fired cases and haven't had any case head separation issues. It doesn't surprise me to see the neck failures since that's the only part of the case that's exposed to the expansion and compression of firing and reloading. I looked closely at the necks of the rest of the fired cases and could see what appeared to be tiny stretch marks on the neck of one other case which I also scrapped. I've heard lots about examining cases near the head for signs of stretching but nothing so far about stretched or cracked necks.

Merc

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Originally Posted by Merc

I sat down to reload a box of PPU .303 Brit and saw something new, at least for me. Five of the cases out of 20 had cracked necks and had to be scrapped. I've been reloading for a few years and these cases have been reloaded many times. I only resize the necks of the fired cases and haven't had any case head separation issues. It doesn't surprise me to see the neck failures since that's the only part of the case that's exposed to the expansion and compression of firing and reloading. I looked closely at the necks of the rest of the fired cases and could see what appeared to be tiny stretch marks on the neck of one other case which I also scrapped. I've heard lots about examining cases near the head for signs of stretching but nothing so far about stretched or cracked necks.

Merc

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I think they call it "work hardening", it happens to metal that repeatedly gets reshaped. It gets brittle over time and cracks. At some point in your usage (after X number of reloadings) you can re-anneal the case necks to return the metal's molecular structure to a "softer", more flexible configuration. It depends if you think the effort to anneal is worth the benefit. With my mild 303 neck loads I can get somewhere between 15 and 20 loads before they begin to crack (depending upon make). If I was concerned about replacement cost of the brass I'd probably have to anneal around load 10 to save them. I did it a couple of times years ago and said the heck with it. Of course if I were loading rare, difficult to get brass I would certainly consider annealing.

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Originally Posted by kcw

I think they call it "work hardening", it happens to metal that repeatedly gets reshaped. It gets brittle over time and cracks. At some point in your usage (after X number of reloadings) you can re-anneal the case necks to return the metal's molecular structure to a "softer", more flexible configuration. It depends if you think the effort to anneal is worth the benefit. With my mild 303 neck loads I can get somewhere between 15 and 20 loads before they begin to crack (depending upon make). If I was concerned about replacement cost of the brass I'd probably have to anneal around load 10 to save them. I did it a couple of times years ago and said the heck with it. Of course if I were loading rare, difficult to get brass I would certainly consider annealing.

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KCW,

Thanks for the info on annealing.

Merc

"...these cases have been reloaded many times..." That'll do it. Like kcw says, it's work hardened brass. Pitch the cracked cases and anneal the rest.
Annealing is easy and costs little. Use a regular propane torch(kit runs about $14 to $20 in Home Depot) and a pan of plain tap water to the shoulder. Heat the case necks and shoulder until the brass visually changes colour and tip 'em over.
Anneal is not part of the regular reloading process. Only needs doing when you get a cracked case mouth.

Changes color - does that mean the case neck begins to glow or does that mean the case neck changes to a lighter color when compared to the rest of the case.

I remember reading a post that suggests that a common way to anneal brass cases is to heat until glowing and drop in water. That probably gets the brass heated to 1000 to 1200 degrees, well beyond the 700 degree temperature that anneals brass. Will that high temperature damage the brass?

Merc

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Originally Posted by Merc

Changes color - does that mean the case neck begins to glow or does that mean the case neck changes to a lighter color when compared to the rest of the case.

I remember reading a post that suggests that a common way to anneal brass cases is to heat until glowing and drop in water. That probably gets the brass heated to 1000 to 1200 degrees, well beyond the 700 degree temperature that anneals brass. Will that high temperature damage the brass?

Merc

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I've always followed the instructions from my circa mid 70's Lyman manual which instructs to stand up a number of unprimed cases on their heads in a metal pan, with water depth at half the length of the brass. Heat neck until "cherry red", at which point push over the piece with the tip of the torch so as to completely submerge the casing. I haven't annealed in years, but when I did the "cherry red" standard worked well in preserving the cases.

Interesting. The water prevents the bottom half of the case from annealing. Thanks for the info.

Merc