# EFMJ -- interesting new ammo



## Vedel (Jul 17, 2007)

here is an entry obtained from defensetech.org on the new expanding full metal jacket round.


Defense Tech infrequent contributor and resident ballistics expert David Woroner busted out an interesting first-person analysis of a bullet that could answer soldiers’ call for more stopping power.

As our readers might remember, we reported two weeks ago that a Center for Naval Analyses study obtained by DT found of all the suggested improvements for America’s standard-issued sidearm and carbine, soldiers surveyed said they want a more deadly weapon or round.

CNA pointed out that one answer is off the table: hollow point ammo.

But Woroner took a first-hand look at a type of round that could answer a politics vs. lethality dilemma…

From Dave (it’s a longish entry, but I think you’ll find it worth the read):

Known as the Federal EFMJ for “expanding full metal jacket” the round would appear to be a gift from above to the soldier on the ground. It is fully jacketed, yet expands like a hollow point upon impact.

The basic concept was developed by projectile whiz Tom Burzynski and Larry Head, lead ammo designer for Federal applied some of his magic to bring this bullet to fruition.

So what makes this round so different and special?

Well first of all it is a “full metal jacketed bullet” - this means there is no “cup” at the front as with most hollow points. Standard hollow points work by taking advantage of fluid dynamics - the fluid being the liquid or blood in a target.

While stopping many a fight and still not a bad choice at all, I personally have seen many hollow points “stay intact” - or not expand. The culprit for this has usually been, believe it or not, clothing. When the “cup” or hollow of the bullet is passing through clothing, especially winter type clothing the hollow point can end up filled as it cuts through the material thus preventing expansion.

What’s also pretty cool about the EFMJ bullet is that because it’s fully jacketed, it feeds flawlessly. Anyone who’s spent some time shooting hollow-point ammo has experienced the hollow “lip” catching on the feed ramp of the weapon – forcing an operator to execute “stoppage drills” in the middle of a gunfight.

Besides overcoming the feeding issue, the EFMJ works unlike a typical hollow point on impact. Think for a minute about firing at a target through drywall with a standard hollow point? Nine times out of ten the hollow point will fill up with the powdery drywall.

EFMJ-web.jpg

Now enter the EFMJ. It works by having a piece of encased lead with a tiny nylon/rubber plug. When it strikes its target, it cannot fill up at the front since it’s encased. Instead, it begins to (for lack of a better word) “smush up” the entire round. How it begins its expansion so diametrically opposed to a standard hollow point and its reliance on fluid hydraulics is that the EFMJ operates solely on impact/kinetic input to the front of the bullet.

Part of the manufacturing process of the EFMJ includes creating “cuts” or striations on the inside of the encasing copper. When the bullet impacts, it begins its expansion by impact/blunt force with the “cuts” splitting and allowing the rubber component to continue to flatten. By then it would have entered its target.

Another test I did was to shoot it through plies of standard drywall and it worked great. It penetrated, started its deformation as well. So when it struck the target behind the wall, the bullet was still full of energy, yet almost fully expanded.

Shooting through two pieces of drywall yielded the same result, except it was obvious there was a slight drop off in connecting kinetic energy. You want to be able to shoot through drywall and plywood and still hit something, but you don’t want it going down the block and kill granny sitting out knitting on her front porch.

The penetration I got was very consistent with current kinetic impact understanding and that gave me even more reason to trust this round. To put it quite simply it is harder to shoot through a piece of glass then it is drywall because the glass is more molecularly compact than the drywall.

So when I shot 9mm and 45cal. rounds through each, I was pleasantly surprised to find that although the rounds did penetrate the glass, the expanded as advertised. Having my caliper in back pocket told me that the 9mm expanded to .51 inches and the 45 cal. to .64 inches (all rounds being caught by foam and soft rubber) those numbers are an average for multiple shots on glass. The 9mm in my opinion in straight up head to head performance came out ahead of the .45, I’m sure only because of the higher velocity of the 9mm round.

On the drywall, I found more expansion but not by much, 9mm to .58 and the .45cal to .67 which for either surface, and the energy carried still after impact was surely enough to penetrate a solid 9-10 inches.

It would be super to see our troops carrying the EFMJ in their Beretta, Colt, Kimber, etc. The next thing Federal needs to do is create the same technology in the 5.56 (.223) round, I would be very interested to see the results of that test.


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## Crusader74 (Jul 17, 2007)

excellent Article...IMO this sheds some light on weather the 9mm has better penetrating power than the .45.

Just outta interest..which is the more expensive??


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## WillBrink (Jul 27, 2007)

Vedel said:


> It would be super to see our troops carrying the EFMJ in their Beretta, Colt, Kimber, etc. The next thing Federal needs to do is create the same technology in the 5.56 (.223) round, I would be very interested to see the results of that test.



There are LEO depts. using the Federal EFMJ. My understanding is results have been spotty and the rnd failed to expand more often than it should (see article below). 

Tests I have seen found it expanded, but not as well as well made JHP. Makes sense the rnd might have specific uses, like in theater where something thats acts like an FMJ/JHP hybrid might be the ticket. Not slamming the rnd just throwing out what I have read on it. Another rnd with similar concept is the Corbon Powerball, which is supposed to feed like FMJ and act like FMJ on hard targets but expand like JHP on soft targets:

http://www.dakotaammo.net/products/glaser/powrball.htm

Article:

Bullets Used By Detroit Police Under Investigation
Expanding Bullets May Not Be Effective, Some Cops Say



Story by Click On Detroit

-- It's a troubling question raised by several recent police shootings.

In one, a bullet fired from an officer's weapon bounced off a suspect's head. Another failed to penetrate a robber's winter coat.

Now the ammunition carried by Detroit police is under attack.

In a front-page story in Wednesday's Detroit Free Press, it was reported the Detroit Police Department has launched an investigation into the use of the .40-caliber bullets the police department uses. The bullets are known as expanding full-metal jackets.

Chief Ella Bully-Cummings said the investigation was launched after a concern was raised by some of the officers using the bullets.

"It was a couple of weeks ago. Some issues were raised and some concerns expressed over the ammo we have. Anytime it deals with the officer's safety I have to be concerned as the police chief, so I asked that we take a look at the ammo that we have," Bully-Cummings told Local 4 during an interview Wednesday.

Bully-Cummings said the switch to the expanding bullets happened several years ago when the police officers union raised an issue with the ammunition being used at the time.

"It had a tendency to over penetrate meaning it was a 'through and through.' Bully-Cummings said the through-and-through bullets allowed a perpetrator to continue advancing towards an officer. Additionally, it presented a hazard to innocent bystanders.

"If it's a through-and-through, that could injure a bystander," she said.

As a result of that arbitration award, the expanding full-metal jacket bullets were instituted with "the whole intent to stop the advancement of the perpetrator," she said.

Two recent incidents – which Bully-Cummings called allegations – raised the concerns of officers, according to the newspaper report.

One took place Feb. 1 when police fired at a robbery suspect who had shot at police officers. The bullet did not penetrate the robber's skull most likely because the man had a metal plate in his head.

The second was the case of another robbery suspect who was shot and wounded by police officers. Further investigation showed that a bullet may not have penetrated a winter jacket the man was wearing.

"We want officers comfortable because their safety is at issue when they are providing public safety for our citizens," said Bully Cummings.

The investigation may take several years, the chief cautioned.

"It is something you just can't rush. It took over four years the first time with the through and through bullet. There is ballistics testing you have to go through, an FBI protocol and I don't want to rush this. I still feel very comfortable with the ammo we do deploy in the department," she said.


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## Olive Drab (Jul 27, 2007)

i heard from a few sources that this has issues especially when hitting a target with heavy clothing (jeans,winter layers, canvas).  i am a fan of speer gold dot 124+p and will continue to use them


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## Vedel (Jul 28, 2007)

*Not for Law Enforcement*

The EFMJ should never be used for police.  Why would they use it? There are tons of other options out there for them.  I use Hornady TAP myself.  No, EFMJ should be looked at as an alternative for FMJ.  For people who can't use hollow point ammo.  Like for instance, the military.  :)    Hell,  when you can have hollow points there are so many options it's sick.  How about DPX?  GREAT rounds.  Powerball,  Federal +p or +p+ hydroshocks,  even Bonded Golden Sabers.  The list is endless.  What I would like to see is a head to head test against FMJ.  If they are better, great it's an improvement.  If not,  why waste your time right?


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## WillBrink (Jul 28, 2007)

Olive Drab said:


> i heard from a few sources that this has issues especially when hitting a target with heavy clothing (jeans,winter layers, canvas).  i am a fan of speer gold dot 124+p and will continue to use them



That seems to be the feeback yes. Cant go wrong with Gold dot or Wichester Ranger.


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## WillBrink (Jul 28, 2007)

Vedel said:


> The EFMJ should never be used for police.  Why would they use it? There are tons of other options out there for them.  I use Hornady TAP myself.  No, EFMJ should be looked at as an alternative for FMJ.  For people who can't use hollow point ammo.  Like for instance, the military.  :)    Hell,  when you can have hollow points there are so many options it's sick.  How about DPX?  GREAT rounds.  Powerball,  Federal +p or +p+ hydroshocks,  even Bonded Golden Sabers.  The list is endless.  What I would like to see is a head to head test against FMJ.  If they are better, great it's an improvement.  If not,  why waste your time right?



Agreed. The tests I have seen are always against JHP as that's the market it competes in most of the time. I  bet the LEO depts that use it do so for PC reasons as it's not those evil JHP rnds. Perhaps we can find tests against FMJ some place on the 'net. Tactical forums are always a good place to look for solid ballistics info BTW.


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