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Old October 16, 2002, 05:33 PM   #1
riverdog
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Cupro-nickel magnetic?

Would you expect a cupro-nickel jacketed bullet to be attracted by a magnet? While my question is about reloading per se, some ammo I recently bought seems to have a steel jacket with a cupro-nickel plating although it's supposed to be a cupro-nickel jacket. Anybody? TIA
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Old October 16, 2002, 06:15 PM   #2
stans
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cupro-nickel jacket material is non-ferrous and therefore would not be attracted to a magnet. Either your bullets have copper plated steel jackets or they have steel cores.
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Old October 16, 2002, 06:38 PM   #3
riverdog
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I took one cartridge for destructive testing and scraped the jacket with a knife. My magnet picked up all the shavings. The jacket is probably mild steel with a cupro-nickel wash.
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Old October 17, 2002, 04:16 PM   #4
Mike Irwin
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What caliber?

What headstamp?

Cupro-nickle doesn't "wash."

It's an alloy that must be draw.
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Old October 17, 2002, 09:04 PM   #5
riverdog
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Mike,
Swiss 5.6 (5.56 M) I found a little more on a web seasrch.
Quote:
Unlike the current NATO which is optimized for a barrel twist of 1 in 7", the GP90 round is optimized for a 1 in 10" twist. This was done to optimize ballistic, accuracy and barrel life. The GP90 also lacks the steel core used by NATO rounds, rather it uses an lead core. The GP90 was originally clad with a nickel jacket, however, this was found to cause excessive barrel fouling, so in 1998 the nickel jackets were replaced with copper jackets. In addition, in 1999 a copper plug was added to the base of the bullet to address environmental concerns.
Rather cupro-nickel, it seems it's either nickel or copper. The stuff I've got is not copper so by process of elimination, it's nickel. Is nickel as magnetic as steel?
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Old October 18, 2002, 05:45 AM   #6
stans
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Nickel is a non-ferrous metal and will not be attracted to a magnet. Only iron and steel (an iron alloy) will be attracted to a magnet. The more nickel or chrome that is added to steel to make stainless will actually decrease the magnetic attraction of stainless steels. Your bullets must be steel jackets with a copper wash.
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Old October 18, 2002, 10:12 AM   #7
riverdog
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Three substances in the world can become magnetic: Iron, Nickel, and Cobalt. These 5.56 rounds may be nickel plated but are exhibiting such a strong pull they appear to be steel jacketed. The attraction is stronger than the penetrator in a M855 round.
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Old October 19, 2002, 06:12 PM   #8
Peter M. Eick
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Now come on guys. Magnetism is a physical property. Everything is magnetic. If I remember graduate school, things can be diamagnetic, paramagnetic and magnetic.

Diamagnetic means it repels in the presence of a magnetic field.
Paramagnetic means it becomes magnetic in the presence of a magnetic field
Magnetic means it attracts in a magnetic field.

Please remember it has been 13 years since I had to define all of that stuff, so I may be a bit rusty.

I did my graduate thesis on how the transition from super-paramagnetic to paramagnetic crystals could be used and how the physics of the transition occurs.

By the way, did you know you can turn most common plastics into electromagnetics? Neither did I and it cost me several months trying to figure out why my susceptibility (measurement of the ease of magnetism) machine would not work right......
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Old October 20, 2002, 01:24 PM   #9
Johnny Guest
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Hi, riverdog - - -

Is this ammo some of that which ammoman.com has been offering from the web site?

Is GP90 the head stamp?

Does anyone have any information as to relative barrel wear characteristics of this type ammo (Shall we call it mild steel jacketed?) as compared to more "normal" milsurp ammo?

I was about to order some of the Swiss 5.56 from ammoman.com, and now I'm having second thoughts. Don't want to put undue wear on (In?) the barrel of my one and only AR15. (Disclaimer: I haven't been in VA or MD in over 20 years.)

riverdog, have you had a chance to chronograph any of your Swiss ammo?

I'll appreciate any additional info.

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Old October 20, 2002, 07:23 PM   #10
riverdog
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I haven't shot any yet. The ammo is supposedly very accurate and as I understand ammoman is almost out.

Don't take my uninformed questions as an indication the ammo is steel jacketed. I was just surprised to see that the ammo was so attracted to a magnet. I did destructively check one bullet (I sectioned it) and it seems to go from nickel to lead; I didn't see any steel jacket. It's advertised as cupro-nickel and nickel is magnetic. If it is steel, it's the mildest steel I've ever seen. Absolutely no problem cutting thru. I'll be storing this for use in a different rifle than the one I have in CA; it's one of those black sheep that doesn't like sunny weather and paperwork
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Old October 21, 2002, 07:34 AM   #11
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Thanks for the information. Guess I'd better order some before they run out.

Best,
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