# Ammo question



## Dano007 (Feb 24, 2015)

Hello all:
Have been reading up on ammo and was wondering what the difference is between full metal jacket and total metal jacket ammunition? Are the terms used interchangably? Can you even buy non jacketed ammo these days.....not that I would want too!!

Thanks


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## Steve M1911A1 (Feb 6, 2008)

In my own way of thinking, the terms are synonymous...except that "total metal jacket" just seems to be a more modern, less precise way of saying "full metal jacket."
"Full metal jacket" is the so-called "term of art." That is, it's the one used by bullet makers and ballisticians.

_However_...
Using "total metal jacket" instead of "full metal jacket" could be making a distinction between two different methods of manufacture.
When a jacketed bullet is manufactured in the standard way, by swedging a jacket around a heavy-metal core, the jacket never really provides "full" coverage. There has to be a hole somewhere. In high-accuracy ammunition, the hole is usually found at the tip of the bullet's nose. In military ammunition, the hole is found at the bullet's base.
But there's another way to build a jacketed bullet: Electroplating. The jacket is electroplated over the heavy-metal core. In this case, there is no hole. The jacket coverage is complete. Perhaps this is what is meant by "total metal jacket."

(I admit that my explanation is merely conjectural.)


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## denner (Jun 3, 2011)

The terms are used interchangeably. Non jacketed ammo is quite common as well in both rifle, revolver and pistol. There is also semi-jacketed ammo which exposes a lead tip.


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## DJ Niner (Oct 3, 2006)

Steve got it technically correct, but denner is also right on the common usage. 

I believe the reloading component company SPEER has trademarked TMJ for it's fully electroplated jacketed bullet, which can be found in SPEER and CCI ammunition, among others. Some indoor firing ranges may require a bullet with an enclosed or covered base, to keep the burning gunpowder from vaporizing some of the lead bullet core that is otherwise susceptible to this problem during firing (the vapor would be left floating around in the air). On a range of this type, TMJ ammo is allowed, along with JHPs (jacketed hollow point bullets, which also have an enclosed base), but not standard FMJ ammo with an exposed bullet base. Ranges with this type of restriction are very rare nowadays; the last one I remember seeing in-person was in a rural Canadian province in the early 90s.


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## denner (Jun 3, 2011)

DJ, thanks' for clearing that up, below is a link from Midway explaining the differing bullet types and their nomenclature.

MidwayUSA ? Shooting Supplies, Reloading, Gunsmithing, Hunting, Ammunition, Gun Parts & Rifle Scopes


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## Dano007 (Feb 24, 2015)

Thanks Guys
Good stuff!!!


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## Cait43 (Apr 4, 2013)

A few years ago I bought a "full metal jacket" but it was so damn heavy I gave it to a knight........... :anim_lol:  :anim_lol:


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## Steve M1911A1 (Feb 6, 2008)

A good knight?
Sleep tight.


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## Sierra_Hunter (Feb 17, 2015)

Actually false. They are close but not the same.

A FMJ is formed by pressing lead into a jacket and forming it into a bullet, leaving the base of the bullet open, and exposing the lead. 

A TMJ is usually platted, or the jacket is two piece leaving no lead exposed at all.


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## Cait43 (Apr 4, 2013)

Google is our friend.........


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## Sierra_Hunter (Feb 17, 2015)

Cait43 said:


> Google is our friend.........


Perfect example of what I was saying.


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## high pockets (Apr 25, 2011)

Sierra_Hunter said:


> Actually false. They are close but not the same.
> 
> A FMJ is formed by pressing lead into a jacket and forming it into a bullet, leaving the base of the bullet open, and exposing the lead.
> 
> A TMJ is usually platted, or the jacket is two piece leaving no lead exposed at all.


Definitely one of the better responses.

Speer calls their bullets TMJ in order to NOT call them "plated" bullets. Plated bullets have long been said to be restricted to lower velocities, and are recommended by most bullet makers to be loaded slower in order to avoid the lead melting through the copper platind and into the barrel.

Modern plating efforts are allowing plated bullets to be driven at the same velocities as jacketed bullets and so bullet makers are scrambling for ways to distinguish their bullets as not being "plated," but are actually Total Metal Jacket (TMJ) and therefore better than plated bullets.

To answer the OPs original question; FMJ are actually lead bullets forced into a thicker copper jacket and are able to withstand higher velocites without the lead melting and causing problems, while TMJ bullets are actually plated bullets and are, therefore, restricted to lesser velocities, unless the manufacturer has gone to the trouble of increasing the thickness of the copper plate in order to allow the bullet to be driven at "jacketed" velocities.


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## Sierra_Hunter (Feb 17, 2015)

Usually I only see TMJ in pistol bullets. I don't think I have seen a TMJ rifle bullet.


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## DJ Niner (Oct 3, 2006)

high pockets said:


> (snip)
> 
> Speer calls their bullets TMJ in order to NOT call them "plated" bullets. Plated bullets have long been said to be restricted to lower velocities, and are recommended by most bullet makers to be loaded slower in order to avoid the lead melting through the copper platind and into the barrel.
> 
> ...


While I believe most of this it accurate, and I also believe that manufacturers would like to use a term other than "plated" for a bullet with a completely encapsulated lead core, only Speer, their related companies (CCI, Lawman, etc.), or companies that they have licensed to do so, can legally use the term "TMJ", as it is a Registered Trademark. Note the letter-R-in-a-circle immediately after the term on this page:

Speer Bullets - TMJ

Some _shooters_ may use the term TMJ for a totally-encapsulated-core bullet, but I'm betting you won't find any other bullet/ammo makers doing it, unless they have an agreement with Speer. Most serious companies are pretty aggressive about protecting trademarks, because if they don't protect it, they can lose it.


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## berettatoter (Sep 1, 2011)

Cait43 said:


> A few years ago I bought a "full metal jacket" but it was so damn heavy I gave it to a knight........... :anim_lol:  :anim_lol:


Funny right there!


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