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Old September 17, 2002, 11:52 AM   #1
priv8ter
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Ball vs. FMJ

Kind of a lame question here, but I have always assumed that ball ammo and FMJ ammo were the same thing. While reading through posts, I notice a lot more people use the term ball ammo, than FMJ. Just for the record, they ARE one in the same, aren't they?
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Old September 17, 2002, 12:09 PM   #2
C.R.Sam
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The terms are generally used interchangeably.

Ball is generally lead core with full metal jacket.
Some spedialty rounds are full metal jacket with added goodies, like incinderary, tracer, AP etc.

Most full metal jacket isn't. Most have the core or added goodie exposed at the base.

Manufacturing expedient. True fully jacketed ammo very expensive and difficult to make. If hollow point, the base is usually jacketed. If solid point, the base is usually exposed. Exceptions of course.

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Old September 17, 2002, 12:19 PM   #3
Ben Swenson
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Quote:
Most full metal jacket isn't. Most have the core or added goodie exposed at the base.
Which is why the manufacturers of plated bullets (basically just lead with a very thin bit of a jacket) came up with TMJ or "Total Metal Jacket".
I'm starting to have a hard time reading the alphabet soup of letters following a bullet's weight. I can deal with FMJ, RN, HP, JHP ... I'm good with those. It's when I run into MCSTSJSPBT (moly coated spitzer tip semi-jacketed soft point boat tail) and the like that I begin to shake uncontrollably and my right eye twitches disturbingly. I need to get that looked at.
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Old September 17, 2002, 12:34 PM   #4
Mike Irwin
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A total metal jacket, with no exposed lead, isn't really all that difficult to manufacture anymore.

Jackets can be electroplated in place quickly, cheaply, and efficiently.

Speer does this with it's Gold Dot bullets.
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Old September 17, 2002, 01:02 PM   #5
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Hmmm... Gotta wonder - can they get the plating uniform? The bullet makers I know start with a highly uniform jacket (J4 usually preferred), and then make the lead fit the jacket.
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Old September 17, 2002, 01:10 PM   #6
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Bogie,
You're spot on. TMJ "jacketing" would be very difficult to ensure was a constant thickness, especially since the bullet is often resized after being electroplated (thus displacing the jacket to some extent). Regardless, I often buy TMJ bullets in .451 for reloading. Not because they're the most accurate whizzbangs on the market, but because they're inexpensive and foul the barrel a bit less than cast bullets. Then again, I don't load .45 for 100 yard shooting. I do get decent enough groups at the ranges I commonly fire .45, though.

To my knowledge, electroplated bullets are not yet commonly made for the high velocity rifle rounds that benchrest and varmint shooters use. You'd know more about that than I.
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Old September 17, 2002, 02:12 PM   #7
Mike Irwin
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Getting highly uniform thicknesses on plated parts is not difficult at all.

Speer is plating jackets that are as uniform in thickness as standard drawn jackets.

The aerospace industry has been doing highly precise plating since the 1960s. It's not uncommon for something to require a gold or platinum layer exactly 4 atoms thick.

Traditionally formed bullets are resized at all points throughout the process, from initial drawing to jacket inserting to final profile forming to final sizing.

In other words, bullets formed in the traditional method are resized more heavily than bullets with electroplated jackets.

Electoplating also has another advantage -- it bonds the core to the jacket at the molecular level, meaning that jacket separations, a problem that can occur with traditionally formed bullets, is virtually unknown.

Also, do NOT make the mistake of thinking that a thin plated layer on cast bullets is the same as a full-thickness jacket that is applied by electroplating.
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Old September 17, 2002, 02:22 PM   #8
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bloody ... you edited your post while I was replying. Ne'er mind.
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Old September 17, 2002, 02:49 PM   #9
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Ball is the US military term for standard ammo, nowadays FMJ but dating back to the days when muzzle loading muskets fired a paper cartridge with a large punkin ball and loose powder tied in a neat package. Recruits had to have two teeth that met in order to enlist. They had to tear open the ca'tridge, pour in powder, ram down ball and paper and prime their piece by the numbers.

FMJ is the civilian term for what the army calls ball. Guess we ole sojers call FMJ ball out of habit.
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