# Difference between FMJ and copper clad...



## Quack Addict (Aug 10, 2006)

I've been reloading for several years and have loaded rounds for my .223 using "FMJ" bullets. One of my favorite target loads for the 223 includes a bullet which has an exposed lead base encased in a relatively thick copper jacket. I am pretty sure these are not SS109, but they are similar profile.

I have loaded FMJ bullets for my 40 S&W that were plated with copper, all the way around. I think these are referred to as "copper clad". 

Question... What is the correct definition for *FMJ - Full Metal Jacket* -- a bullet with an exposed lead base (thicker jacket) or a copper clad projectile with a jacket only a few thousandths thick? Can a bullet with an exposed lead base truly be considered a FMJ?


----------



## Ruger1 (Sep 27, 2004)

FRom a Google search:

*full metal jacket bullet* 
_For the Stanley Kubrick film, see Full Metal Jacket._ A *full metal jacket* bullet (or *FMJ*) is a bullet encased in a copper alloy such as gilding metal, cupronickel, or a steel alloy shell. This shell can extend around all of the bullet or often just the front and sides with the rear left as exposed lead. The jacket allows for higher muzzle velocities than bare lead without depositing significant amounts of metal in the bore. It also prevents damage to bores from steel or armor piercing core materials. This bullet type distinguishes itself from hollow point bullets.

*History*

Full metal jacket ammunition is acceptable for military use by the countries that signed the Hague Convention of 1899, which prohibits the use of hollow point or expanding bullets in war between the countries which signed that agreement. It is often incorrectly stated that the prohibition is part of the Geneva Conventions, and that full metal jacket bullets are specifically required. Although the actual language is rather vague, full metal jacket bullets remain the best option available to stay within the letter and the spirit of the Hague convention. The bullet itself is still highly lethal when fired at close range.

*Advantages*

Because the bullet does not expand as hunting bullets are designed to, FMJ bullets are much more effective at armor-piercing. They can cause more damage when the enemy is behind a barricade or when the target is a vehicle or other material. They are also more durable and stand up to rough handling on the battlefield.

**********************************************************************************************

Not sure what the difference is between "FMJ" and "Ball ammo." Never really heard the term "copper clad" before. Some .22 rimfire ammo has what I would call a "copper wash." Wouldn't quite call this "copper clad." Wouldn't call S&W 40 bullets "copper plated." "Plating" generally refers to a process whereby a metal film (copper, chrome, nickel) through a chemical/electrical process is caused to adhere to another metal such as steel - as in "nickel-plated " revolvers. In FMJ or ball ammo a lead core is mechanically encased in a copper "jacket."



Ruger1


----------



## Huntsman27 (Sep 29, 2004)

There are plated bullets out there, its a cost effective way of bringing bullets to the market. Instead of using copper guilding metals [much thicker] the electroplate is cheaper for them to make bullets with. With the costs of copper and brass skyrocketing, manufacturers will surely be looking for ways make cash with alternatives. Wolfs Bi-metal bullets are one example of this. Cheaper than FMJ copper guilding, and lets them bring their ammo in below what Win/Rem/Fed and sell a lot more.
As Rugers comment shows both styles of bullet can be fully encased or have an exposed bottom. The Jacket really only need cover the cone of the jacket to be FMJ.


----------



## alex-v (Mar 24, 2005)

Ruger1 said:


> Not sure what the difference is between "FMJ" and "Ball ammo."


The "ball ammo" terms goes back about 100 years and refers to the standard bullet profile that is still used for the 45 ACP. The rounded nose fed up the feed-ramp without hanging up. When loaded in a 45 ACP case only the nose stuck out since the sides of the bullet were inside the case unlike many revolvers bullets. This makes it look like a "Ball".

These days many of the 230 grain 45 ACP RN bullets are copper jacketed. The ball look to the loaded round is just like the older style lead bullets so many will refer to copper jacketed as ball ammo.

It is the profile of the bullet and not the materials.


----------

