do projectiles harden

can anyone tell me do projectiles harden over time have been using the same projectiles for a few years now that i got in bulk have never had a prob in the past till recently as im getting no real mushroom effect anymore please help

I cant fathom how they would? copper can work harden but this has allready been done by swaging around the core

Slower impact speed, smaller, softer targets, would lead to less expansion.

have been using the same formo for years now as it works best for me but lately can shoot through both shulders with very littel mushroom

Any alloy will harden with age at room temp, especially if it has any traces of copper, magnesium zinc or IIRC silicon - there may be more elements.

Mag wheels, race flywheels etc - the billets are left out in the weather for years before being machined.
I have a photo somewhere where I was at a top Japanese racecar workshop, and out the back they would have had 500 billets sitting in the weather aging - been there for 5 years
My understanding through limited japanese/chinglish communication that it was for stress relief and hardening.

Copper and brass thats left for a long time will anneal very slowly at room temp, add heat and the process is sped up.
Consider brass cases, in which get harder when fired and requires heat (annealing) to bring them back to required neck tension etc - but you're adding heat when firing each time which should make them softer...... but the working of the brass make is harder - moreso than the effect of the heat softening

As you can see, the above statements contradict each other somewhat.
I dont know/remember much more technically about it - I'm sure there is heaps of info on the net about age hardening of alloys

I have spoken with someone that agreed with your findings of a box of bulk projectiles that had sat on the window ledge in the shed for years.
Over time they shot worse and performed worse on animals - as if they were harder.
How old are the projs? maybe the deer are evolving and getting softer?? :D

Quote:

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Originally Posted by Spanners

Any alloy will harden with age at room temp, especially if it has any traces of copper, magnesium zinc or IIRC silicon - there may be more elements.

Mag wheels, race flywheels etc - the billets are left out in the weather for years before being machined.
I have a photo somewhere where I was at a top Japanese racecar workshop, and out the back they would have had 500 billets sitting in the weather aging - been there for 5 years
My understanding through limited japanese/chinglish communication that it was for stress relief and hardening.

Copper and brass thats left for a long time will anneal very slowly at room temp, add heat and the process is sped up.
Consider brass cases, in which get harder when fired and requires heat (annealing) to bring them back to required neck tension etc - but you're adding heat when firing each time which should make them softer...... but the working of the brass make is harder - moreso than the effect of the heat softening

As you can see, the above statements contradict each other somewhat.
I dont know/remember much more technically about it - I'm sure there is heaps of info on the net about age hardening of alloys

I have spoken with someone that agreed with your findings of a box of bulk projectiles that had sat on the window ledge in the shed for years.
Over time they shot worse and performed worse on animals - as if they were harder.
How old are the projs? maybe the deer are evolving and getting softer?? :D

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i mite be rong but i dont think thay are getting softer. but you rase a good point as the projcetiles may be six or so years old now but im finding it a bit of a pissoff latley witch is why i asked

Hence why I say it contradicts itself, both age hardening and annealing.

Maybe the lead does something also? I dont remember much about lead.

If someone had a Rockwell hardness tester they could have a play and confirm

Mythbusters need to deal with it :D
Attachment 556

"do projectiles harden" Well most won't admit it but an Amax all dolled up with Redbits has been known to harden :thumbsup:

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Originally Posted by LJP

"do projectiles harden" Well most won't admit it but an Amax all dolled up with Redbits has been known to harden :thumbsup:

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:pacman:

Quote:

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Originally Posted by Spanners

Any alloy will harden with age at room temp, especially if it has any traces of copper, magnesium zinc or IIRC silicon - there may be more elements.

Mag wheels, race flywheels etc - the billets are left out in the weather for years before being machined.
I have a photo somewhere where I was at a top Japanese racecar workshop, and out the back they would have had 500 billets sitting in the weather aging - been there for 5 years
My understanding through limited japanese/chinglish communication that it was for stress relief and hardening.

Copper and brass thats left for a long time will anneal very slowly at room temp, add heat and the process is sped up.
Consider brass cases, in which get harder when fired and requires heat (annealing) to bring them back to required neck tension etc - but you're adding heat when firing each time which should make them softer...... but the working of the brass make is harder - moreso than the effect of the heat softening

As you can see, the above statements contradict each other somewhat.
I dont know/remember much more technically about it - I'm sure there is heaps of info on the net about age hardening of alloys

I have spoken with someone that agreed with your findings of a box of bulk projectiles that had sat on the window ledge in the shed for years.
Over time they shot worse and performed worse on animals - as if they were harder.
How old are the projs? maybe the deer are evolving and getting softer?? :D

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Which one?

That was at JUNs machine shop.
I took the boys from my old shop to Tokyo Auto Salon and toured JUN Machine, JUN engine, RE Amemiya, Knightsports, Tomei, Mazdaspeed, NISMO, Top Secret, and bunch of wee workshops out at the Tsukuba circuit among others.

As I understand it aging IE lathe beds etc has more to do with stress relief and gradual realignment of the grain structure than anything to do with hardness but this is cast iron and alloys could be different:chop:
Are you sure they are not opening? would generally cause(with a pointed type projectile) a smaller than caliber wound both sides and very very little bruising around the hole.
Is it possible that lately you have been shooting at longer ranges than you used to? The lower impact velocity of longer range shots could turn the perfect pill into a drill bit.
Or have the last few you have shot been lucky/unlucky No bone shots where previously you have always got a bone(even if only a onside rib)
By some kind of error could you possibly have loaded to a lower velocity? maybe a new batch of powder? memory error?

I'm not saying its impossible that they have hardened over time it just seems unlikely to me.

Quote:

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Originally Posted by Spanners

That was at JUNs machine shop.
I took the boys from my old shop to Tokyo Auto Salon and toured JUN Machine, JUN engine, RE Amemiya, Knightsports, Tomei, Mazdaspeed, NISMO, Top Secret, and bunch of wee workshops out at the Tsukuba circuit among others.

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You are a lucky bastard! I would give an arm, leg and possibly a testicle to go see those workshops.

Sorry for getting off topic.

I have a mate whos on a first name basis with most of them - been every year since late 90s, although we havnt been back since 08 - might go back this year and spend a bit of time down Sth

F#@K! Sounds awesome. Does Smokey Nagata at Top Secret still do big burnouts?

Took us for a hack down rd in Supra - gave me a Anorak :)
Fella from Knightsports was crazy! tapped out by Narita Airport in supercharged RX8

Wicked. That Supra got him arrested in England I think.

Damn Spanners, thats awesome. I am supposed to be going to sema Next year for work. TAS would be awesome. Do you still own a shop?

Nope - best thing I ever did getting out of the game - build the odd motor and do a bit of tuning on the side still.

Made good money, but I make a shitload more and only wk 6 months a year now.

I see. I only ask as I am in Parts, selling oil now, but been in it for a few years.

Back to bullets, what's the sample size we're talking about here with noticing the projectiles "not performing like they used to"

Quote:

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Originally Posted by gimp

Back to bullets, what's the sample size we're talking about here with noticing the projectiles "not performing like they used to"

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ive noticed it the last few times ive been out so mybe the last 10 rounds ive fired in anger. i will say that thay have been at pigs and not deer but a feed for the famlys a feed

Quote:

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Originally Posted by Spanners

Any alloy will harden with age at room temp, especially if it has any traces of copper, magnesium zinc or IIRC silicon - there may be more elements.

Mag wheels, race flywheels etc - the billets are left out in the weather for years before being machined.
I have a photo somewhere where I was at a top Japanese racecar workshop, and out the back they would have had 500 billets sitting in the weather aging - been there for 5 years
My understanding through limited japanese/chinglish communication that it was for stress relief and hardening.

Copper and brass thats left for a long time will anneal very slowly at room temp, add heat and the process is sped up.
Consider brass cases, in which get harder when fired and requires heat (annealing) to bring them back to required neck tension etc - but you're adding heat when firing each time which should make them softer...... but the working of the brass make is harder - moreso than the effect of the heat softening

As you can see, the above statements contradict each other somewhat.
I dont know/remember much more technically about it - I'm sure there is heaps of info on the net about age hardening of alloys

I have spoken with someone that agreed with your findings of a box of bulk projectiles that had sat on the window ledge in the shed for years.
Over time they shot worse and performed worse on animals - as if they were harder.
How old are the projs? maybe the deer are evolving and getting softer?? :D

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Alot of Italian gun houses will leave barrel steel outside for 12 months for the very same reasons......stress relief. :)