What does "attracts a magnet" mean?

[jpuke]

This question is not as stupid as it looks.  I've been looking at CMP ammo and they say that some "attracts a magnet".  Does this mean it's a steel jacketed bullet or steel core or something else?  Will this wear an M1 barrel faster?  Any experience with this is helpful.  Thanks. 

[Chuck White]

You are correct, "attracts a magnet" means a magnet will stick to it!   It's made of steel in other words.

I don't really know how much more your gun will wear by shooting steel jacketed bullets, but they will wear on your barrel more than copper or lead bullets!
Someone else might be able to fill you in on the "wear factor".

[Mikey]

Attracting a magnet means there is some steel in those slugs.  If you are testing a loaded cartridge, make certain it is the bullet and not the case that is steel.  45 acp ammo was made with steel cases as was other mil-spec ammo but I do not think the bullets were made of steel - that is a quick way to wear a barrel right out and I don't think any ammo makers or mil-spec requirements mandated that. 

It might be more than likely that your slugs have a steel core.  The bullet would be a brass jacket with a steel core.  The desing was for an armor piercing bullet - the bullet would strike the object and the steel core, or penetrator would continue on after the brass had stopped, penetrating the target.  This is the same as the steel penetrator rounds used by tanks to kill other tanks:  the brass bullet casing would shatter on impact against the cold rolled steel turret or body but the steel penetrator would carry on through the turret or tank body - it would make only a quarter inch hole but it would send 2 feet or 1/4 steel fragments through the tank (called the Spaulding Effect, I believe) and it is those fragments that would whirl around the inside of the tank killing the crew. 

They also used a shaped charge in some tank killer rounds for the same effect, I believe. 

In the 06 and other small arms ammo, armor piercing rounds were used to defeat light metal vehicles.  I know that at 100 m some of this older armor piercing ammo shoots on through metallic silhouette targets.  You might have some of this stuff.  JMTCW.  Mikey.

[fastbike]

Current steel core .223 rounds are copper jacketed. FWIW, the effect described from tank rounds is "spalling". Its a term used to describe failure of a material where parts of the surface peel or break away. The effect inside a tank is not so much from the penetration but from the shock wave passing through the hull. At any rate, nasty to be on the inside. Same effect from small arms penetrators, just a lot more limited (besides the penetration).

Shaped charge creates a plasma jet that burns through the armor. Some spalling, but mostly super hot plasma that dissipates its heat on the crew.

Attracting a magnet means there is some steel in those slugs.  If you are testing a loaded cartridge, make certain it is the bullet and not the case that is steel.  45 acp ammo was made with steel cases as was other mil-spec ammo but I do not think the bullets were made of steel - that is a quick way to wear a barrel right out and I don't think any ammo makers or mil-spec requirements mandated that. 

It might be more than likely that your slugs have a steel core.  The bullet would be a brass jacket with a steel core.  The desing was for an armor piercing bullet - the bullet would strike the object and the steel core, or penetrator would continue on after the brass had stopped, penetrating the target.  This is the same as the steel penetrator rounds used by tanks to kill other tanks:  the brass bullet casing would shatter on impact against the cold rolled steel turret or body but the steel penetrator would carry on through the turret or tank body - it would make only a quarter inch hole but it would send 2 feet or 1/4 steel fragments through the tank (called the Spaulding Effect, I believe) and it is those fragments that would whirl around the inside of the tank killing the crew. 

They also used a shaped charge in some tank killer rounds for the same effect, I believe. 

In the 06 and other small arms ammo, armor piercing rounds were used to defeat light metal vehicles.  I know that at 100 m some of this older armor piercing ammo shoots on through metallic silhouette targets.  You might have some of this stuff.  JMTCW.  Mikey.

[John Traveler]

US and foreign Military small arms ammunition specifications routinely specify guilding metal clad steel jacketed bullets.  Throughout much of the Korean War thru post Vietnam War era, 7.62x51 NATO, .30 M2, .50 BMG, .45 ACP, .38 Special, and M1 Carbine bullets were made of lead-filled mild steel "copper" plated jackets.  The steel used was thin and relatively soft, like that on a "tinned" can, but was readily detected using a magnet.  These alternative specs were developed for wartime manufacturing to conserve strategic materials like copper.

Extensive firing of steel-jacketed bullets will result in more bore wear, but for anything less than heavy competition practice or machine gun use, the difference in barrel life between steel and non-steel jackets is insignificant.

HTH
John

[Mikey]

John, Fastbike:  Thanks guys.  I never knew about the steel jackets on the ammo we used in Vietnam.  It all looked like brass jacketed stuff to me and it didn't seem to matter what it was when it hit. 

Nasty stuff those penetrators.  That plasma effect sounds absolutely fatal.  Mikey.

[fastbike]

It definitely can't be a great day to be a tank crew.

John, Fastbike:  Thanks guys.  I never knew about the steel jackets on the ammo we used in Vietnam.  It all looked like brass jacketed stuff to me and it didn't seem to matter what it was when it hit. 

Nasty stuff those penetrators.  That plasma effect sounds absolutely fatal.  Mikey.

[Larry Gibson]

The "steel" jacketed bullets are plated with gilding metal (copper zinc alloy) and the steel part does not touch the bore, the lands or the grooves. They do not wear the bore any faster than plain copper jacketed bullets. In military barrels the heat from the powder combustion will burn the barrel out long, long before any friction from the bullet, steel jacketed or not, does.  The misuse of a cleaning rod by soldiers does far more damage to barrels than bullets ever will!.

Larry Gibson

[Val]

Some rifle ranges do not permit the use of ammo containing steel.

[tomzuki]

Yup!  Causes brush fires here out West..........

[kombi1976]

Current steel core .223 rounds are copper jacketed. FWIW, the effect described from tank rounds is "spalling". Its a term used to describe failure of a material where parts of the surface peel or break away. The effect inside a tank is not so much from the penetration but from the shock wave passing through the hull. At any rate, nasty to be on the inside. Same effect from small arms penetrators, just a lot more limited (besides the penetration).

Shaped charge creates a plasma jet that burns through the armor. Some spalling, but mostly super hot plasma that dissipates its heat on the crew.

Or, of course, you can use rounds with a depleted uranium tip and they penetrate well too killing the crew.
They also have that wonderful long term effect as they often make their way into the local water table or lie among the debris in the bottom of the tank for local kids to play with.
Just check out an aircraft called the Warthog which sports a Gatling style cannon in the nose and see how much of those depleted armor piercing rounds they can put into a 1 metre square in a minute.
I believe they've been used a lot in 'Stan and in Iraq.

[Slamfire]

The composition of the original bullets for the 6.5x55 was an iron brick, sandwiched between two layers of copper. The brick was heated and rolled until it reached jacket thickness, then filled with a lead core. They'd most likely attract a  magnet. Some later Italian ammo for the 6.5x52 would also. 

[WILDCATT]

AMERICAN MILITARY BULLETS WERE MADE OF STEEL WITH LAYER OF COPPER ON BOTH SIDES.THEY DO NOT WEAR THE BARREL ANY MORE THAN ANY OTHER BULLET

[NavyLT]

AMERICAN MILITARY BULLETS WERE MADE OF STEEL WITH LAYER OF COPPER ON BOTH SIDES.THEY DO NOT WEAR THE BARREL ANY MORE THAN ANY OTHER BULLET

WHY ARE YOU YELLING?!?  WE'RE NOT DEAF!  Just because you are correct is no reason to YELL!

[Brithunter]

Hmmmmm if you check a lot of sporting  i.e hunting ammo like RWS and Norma to name but two you will find that there is a great likely-hood of them attracting a magnet as the jackets are plated Sintered Iron. ..................................... And yes they do expand 

Norma was changing over to a material called Tombac ........................... not to improve bullet performance but to increase tooling life according to the Norma booklet I have here somewhere.

As for sparking bullets unless they are tracer or incendiary I think someone has beeing watching too many movies or TV.

[Larry Gibson]

Hmmmmm if you check a lot of sporting  i.e hunting ammo like RWS and Norma to name but two you will find that there is a great likely-hood of them attracting a magnet as the jackets are plated Sintered Iron. ..................................... And yes they do expand 

Norma was changing over to a material called Tombac ........................... not to improve bullet performance but to increase tooling life according to the Norma booklet I have here somewhere.

As for sparking bullets unless they are tracer or incendiary I think someone has beeing watching too many movies or TV.

I've busted lots of steel and rocks over the years with soft steel jacketed surplus bullets from numerous countries and none sparked. What did spark was the 7.62x39 surplus ammo imported in quantity that had a soft steel penetrator in the tip of the bullet. These would spark on steel and on certain types of rocks.  It was this type of ammo that caused several fires in southern California. The result was a banning of ALL FMJs on numerous ranges and shooting sites.

Larry Gibson

[Brithunter]

Hmmm never seen any of that Ammo but then again I have never had a rifle which took it.

[whynot]

Cupro-nickel jacketed bullets will stick to a magnet, as well.