M80 Ball- Steel Jacketed?

[.455_Hunter]

Greetings,

Is milspec 7.62x51mm M80 ball steel jacketed?

My buddy just bought a box of WWB 7.62x51 and we were surprised when a magnet stuck to the bullet.

Thanks,

Hunter

 

[Kurt_D]

Yes, copper washed bimetal jacket

 

[Z-Michigan]

Some of it is, some of it is not, it changes seemingly randomly and you cannot get information from the box or carton it's in. Seriously.

I believe that most of it lately is steel jacketed. You should assume it is unless you know otherwise. It is quality stuff and the only reason to avoid it would be if you are using a range that prohibits steel jacketed ammo. The copper plating is thick enough that there is no significant difference in bore wear from using it vs. copper FMJ.

 

[Ed Harris]

In US cal. .30 ('06) and 7.62 Linked pack intended for machinegun use is gilding metal-clad steel, abbreviated as GMCS, as this is less subject to "stripping" when fired in long bursts from heated barrels. Jacket stripping test done during ammo acceptance is a 100-round continuous burst, checking the composite group on a witness card fired at 50 meters, there can be no tipped shots or keyholes outside the main group.

Boxed or clipped pack intended for rifle use is generally 90/10 gilding metal, abbreviated GM, which is a bit easier on bores. AP ammunition is also GM jacketed to ease breakup and more easily release the penetrator core.

 

[.455_Hunter]

This is great info!

Is there a terminal performance difference between the two types? It seems that the GMCS would offer better barrier penetration, and perhaps less effectiveness on soft targets...

 

[-v-]

I do recall hearing that if the jacket is heat-treated correctly, it will actually perform better on soft targets as it will have a tendency to shatter on impact and expose the lead core plus all kinds of other secondary effects.

 

[Ed Harris]

The design standards for ammunition that can be called "NATO" ammunition do not specify bullet jacket material or jacket thickness. The construction of the West German 7.62 mm NATO bullet differs from the US 7.62 mm NATO round in that, the jacket material is copper plated steel, whereas the US version is copper (or the so called gilding metal alloy, which is predominantly copper).

The West German steel jacket is about 0.6mm thick near the cannelure and the US copper jacket is about 0.8mm thick at the same point. This design difference is responsible for a vast difference in performance in tissue. The German bullet, after travelling point-forward for only about 8 cm, yaws and breaks at the cannelure. The flattened point section retains only about 66 % of the bullet's weight, the remaining 45 % mass becomes fragments (Fig. 8). The wound profile can be described as an enlarged M16 profile (Fig. 3), with dimensions of the tissue disruption increased by 60 % (temporary stress cavity about 22 cm diameter; permanent crush cavity about 11 cm diameter, penetration depth of the bullet point about 58 cm).

The uncomplicated thigh wound from this bullet is likely to have a large exit with the loss of substantial tissue near the exit; still, this might not be a very serious wound since the bullet fragmentation does not occur until beyond 10 cm penetration depth and, in most shots, the bullet will have passed well beyond the major vessels before this occurs. The abdomen shot, however, because of the much enlarged permanent cavity from bullet fragmentation, is likely to prove fatal in a majority of cases.

Some references:

http://www.firearmstactical.com/images/Wound%20Profiles/M80.jpg

http://www.uthr.org/SpecialReports/Military_rifle_bullet_wound_patterns.htm

http://rkba.org/research/fackler/wrong.html

 

[Float Pilot]

s there a terminal performance difference between the two types? It seems that the GMCS would offer better barrier penetration, and perhaps less effectiveness on soft targets...

It ball ammo so it will never have good performance on soft targets, compared to hunting ammo. However the steel used in the jacketing is very mild in hardness and it is not going to be predictable in how much better it penetrates barriers over a copper-bronze jacket. I have some Norma hunting bullets which use a magnetic jacket and they still mushroomed inside a brown-bear.
On the other hand I have also tested some real black tip AP ammo with a magnet and it did not stick. The levels of chrome and other none-magnetic elements must have far out-weighed the iron in the mix.

If people start mis-stating that ball ammo is nearly the same as AP, then the feds will close that door as well.