HP vs EFMJ

[Lupinus]

So I was trucking around federals web site and looking at ballistics and came across expanding full metal jacket rounds under their premium personal defense. Now I know how HP's work but what about EFMJ? I know next to nothing about them.

Now as to strategies and tactics? Well I want to know where they might be better to use them Hydrashocks or other HP types ammo. I am guessing that the EFMJ offers better penetration? According to their ballistics the EFMJ offers more energy, the 165 grain EFMJ offering 476 with the 165 grain hydrashock offering 412.

 

[rdbrowning]

They have a Full Metal Jacket that has been scored on the inside. Inside is a rubber (silicone?) ball that allows the jacket to collapse and expand, separating along the internal scores much as any jacketed hollow point.

I read a review on them a year or so ago. They were developed to feed in an auto and to prevent the potential problem of a HP getting filled with debris and acting like a solid. The article tested them against regular HP's, shooting into fabric covered gel and non-covered gel. The EFMJ were more consistent than the HP.

I will try to find the article and post a link.

eidit to add link:
http://www.greent.com/40Page/general/EFMJ.htm

here is a pretty good review of EFMJ.

 

[Lupinus]

thanks, they seem interesting and it does make sense that they cant get clogged if there is nothing to clog. Plus the 64 pounds of energy difference is interesting. PLus seems like it would get better penitration then a HP round.

 

[WT]

Detroit PD is less than happy with EFMJ's.

____________
Cops: Ammo lacks punch

Detroit Police Department starts investigation after word spreads that special bullets fail in crucial situations
February 23, 2005
BY BEN SCHMITT
FREE PRESS STAFF WRITER

Detroit police officials are investigating the ammunition officers use after a bullet fired from a cop's gun bounced off a suspect's head and another bullet failed to penetrate the winter jacket of a suspected robber.

These two recent incidents -- and rumors of others -- have touched off a fierce debate that's raging from patrol cars to the gun range to the chief's office. It's a sensitive topic in a department under federal supervision, partly because of complaints about excessive force.

Chief Ella Bully-Cummings ordered the investigation.

The .40-caliber bullets are manufactured by Federal Cartridge Co. of Anoka, Minn. They are known as expanding full metal jackets.

 

[Lupinus]

yeah...but thats Detroit

I'm thinking the better penitration could be a plus esspecialy if you have cold weather with people wearing heavy winter jackets.

 

[WT]

Let me put it this way.

EFMJ is so BAD it is approved for use in New Jersey.

 

[Creeping Incrementalism]

Detroit police officials are investigating the ammunition officers use after a bullet fired from a cop's gun bounced off a suspect's head and another bullet failed to penetrate the winter jacket of a suspected robber.... The .40-caliber bullets are manufactured by Federal Cartridge Co. of Anoka, Minn. They are known as expanding full metal jackets.

This guy I know know's this other guy who works there who said Federal played a joke and actually sold the Detriot police rubber bullets.

 

[RyanM]

EFMJ should only be used in jurisdictions where hollowpoints are illegal, or if you are somehow forced to choose between EFMJ and a previous generation hollowpoint. They actually expand less consistently when fired through cloth than current generation hollowpoints. They also exhibit less penetration and less expansion, compared to conventional HPs of the same weight and velocity. I.e. a 124 gr at 1100 JHP load may expand to 0.56" and penetrate 13.0", but a 124 gr at 1100 EFMJ load will probably only expand to .52" and penetrate 12.5". This estimate is based on actual data.

http://www.tacticalforums.com/cgi-bin/tacticalubb/ultimatebb.cgi?ubb=get_topic;f=78;t=000046

As you can see here, 1 in 5 EFMJs failed to expand through heavy clothing. With a modern, high quality hollowpoint, like Gold Dot, Golden Saber, HST, or Ranger T, you can expect them to expand nearly 100% of the time through heavy clothing.

Previous generation hollowpoints, however, like Hydra-Shoks and Silvertips, expand about 5% of the time through heavy clothing. That is, they fail 95% of the time. EFMJ is better than those HPs, but worse than the latest.

EFMJs are not very likely to feed better than current HPs, given the broad truncated cone shape of the EFMJs. If your gun is finicky, I suggest testing Golden Sabers, since they very closely approximate the profile of ball ammo.

 

[JShirley]

I can't speak for all EFMJ of course, but the 124-grain both expanded and penetrated in dead deer.

J

 

[Nicky Santoro]

http://www.raoulwagner.com/tests2005.htm

FWIW
YMMV

 

[benEzra]

Detroit police officials are investigating the ammunition officers use after a bullet fired from a cop's gun bounced off a suspect's head and another bullet failed to penetrate the winter jacket of a suspected robber.

I want to know where you can get those NIJ Level IIA rated winter coats...

Seriously, there's no way a winter coat is going to stop ANYTHING traveling 900 fps. IF this story is true, it must have been a squib load/no powder...

 

[crofrog]

I want to know where you can get those NIJ Level IIA rated winter coats...

Seriously, there's no way a winter coat is going to stop ANYTHING traveling 900 fps. IF this story is true, it must have been a squib load/no powder...

It depends on what it went through before it got there.

 

[ghost squire]

The .380 ACP equivalent cartridge the Italians used in their Villar Perosa SMGs in WWI would often bounce off of the Austrian soldier's winter coats, leaving nothing worse then a bruise underneath. It's not hard for me to believe that something going faster would penetrate but stop in the layers of it.

 

[Shawn Dodson]

The nose collapsing may have had something to do with it.

Kind of like the front end of a car crumpling to absorb energy in a collision.

Of course, as the bullet nose collapses it expands, increasing its surface area and decreasing its sectional density.

 

[david_the_greek]

Being in Detroit its not at all inconceivable that the jackets many people wear might clog up a HP or EFMJ. many of those jackets are thicker than I am. I'll have to confer with my SRT friend though has he would probably be alot more informed has he has been on the Detroit police force for most of his adult life and that would be for a very long time. and Detroit does get cold weather... or atleast really bad and confusing weather.

 

[chopinbloc]

sounds like a job for ol' painless. i'm surprised he hasn't done a box o' truth on this one yet.