Fire Forming to harden case heads....do you?

BoomFlop

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My 7 Sherman Short should be finished any day now. I have 200 pc of ADG brass from Rich, 2000 Fed 210m, 8lb RL 26 and 1000 Berger 180 Hybrids to start with. My question is, I was planning on firing 56 gr of RL 26 (minimum charge) to case harden the head. It will form to my chamber as well, however, the main reason would be to harden the head to make the brass last longer.

Thoughts? Do you? Waste of time?

Thanks all,
Steve
 

Beluebow

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I do a mild load on the first firing......I'm not sure it makes a difference....The internet tells me it does. 🤪
 

sveltri

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I just did it for the first time for my 6.5x47 Lapua, only time will tell if it made a difference.
 

BoomFlop

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Rich said, he wouldn't load more than 57 grains the first time. Case hardening the case head is suppose to hold primer pockets much longer versus hitting it with an upper end load right away.
 

243winxb

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Not sure how it gets "work hardened" Could be when the brass is formed? i don,t know. My case heads, primer pockets don't expand, are not sized, cant see how it can be work hardened when FL sizing?? Unless spring back does it??

Olin Brass had posted this-
"modulus of elasticity- Cartridge Brass-
Material is 70 copper/30 zinc with trace amounts of lead & iron , called C26000. Material starts to yield at 15,000 PSI when soft (annealed), and 63,000 PSI when hard.
Material yields, but continues to get stronger up to 47,000 PSI when soft, and 76,000 PSI
when WORK HARDENED. Modulus of Elasticity is 16,000,000 PSI. This means to pull a 1.000 inch long strip to 1.001 inch long induces a 16,000 PSI stress.
So if you pull a 1.000 inch strip to 1.005 inch long, you get about 76,000 PSI, which is the max obtainable."


If you anneal the brass neck and shoulder, the case body gets stress relieved when it reaches about 400 degrees. From Gov on 5.56 ammo fired in full auto. 1 less annealing caused separations.
 
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GLTaylor

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I use moderate loads to fire form brass. Purpose of moderate loads is to reduce primer pocket expansion unnecessarily - or at least that's what I've always believed. At full pressure/high pressure, pockets only last so many firings before becoming loose.
If I get 6 loadings out of my Shermans, I'm satisfied?
 

BoomFlop

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That is the purpose. Not to over expand the case head with a upper end charge. The first loading is a nice easy load, which still expands case head some, which in turn hardens the head. This process is suppose to make the primer pockets last longer as they become harder and will not expand much over the remaining firings.
 

sedancowboy

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I have been using ADG brass since it became available. I have have also been loading for 50+ years.
If you were using Nosler or Fed brass I might say yes. ADG has some of the hardest case heads in the industry and I don't think you will be able alter the hardness of it by firing it one time.
 

BoomFlop

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@sedancowboy

So you would do load work up right away and don't feel it would extend the brass life at all? Then just modify load after barrel speed up, and then on 1x fired brass?
 
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