armor piercing bullets

Factual Questions
1

I was wondering what separates these from other bullets, specifically full metal jacketed ones.

2

A standard FMJ generally features a lead core clad with copper – both are relatively soft metals, not designed specifically to pierce armor. Armor-piercing rounds, on the other hand, have a steel jacket over a dense core – lead or even depleted uranium – and are specifically designed to hold together and penetrate armor.

3

Harder (to prevent expansion on impact). Heavier (to carry more energy). Prettier to look at.

4

AP rounds often have much sharper tips, and can be coated with teflon to allow them to pass through body armour. They may also have a ceramic or other non-metallic penetrator tip that will not deform, giving them better armour penetrating power. I believe that AP rounds are generally fired at higher velocity to give them more punch, but I’m not sure about this.

5

Howdy, Mr Urt - nice to see you jump out of “lurk status.” Let’s see if we can sort out some stuff here… Bullets are coated with teflon (ala the old KTW “cop killer bullet”) to protect the bore of the firearm from the extremely hard (and sometimes, dense) metal used to construct the bullet. The teflon really does nothing to assist in defeating body armor.

Modern AP rounds (and others such as API and Tracer) for small arms look exactly the same as FMJ rounds, except they have a different colored tip. This is to distinguish them from FMJ. I have not seen ceramic or non-metallic tips on AP rounds, but they may exist outside my experience.

The problem, of course, with using AP rounds is that they achieve over-penetration of targets other than for which they were intended. This could be dangerous for persons on the periphery of, or behind, the aiming point on “soft” targets.

6

Teflon coating has nothing to do with penetrating ability, it is used to reduce barrel wear from bullets made of materials that are harder than lead/copper. Link

7

Testing, testing, testing… can y’all see me? Oh, okay… sorry for the interruption. Thought maybe I had gotten some of that invisible ink into my keyboard, somehow.

8
      • As far as regular M-16/5.56 ammo goes (and most other small arms):
  • a regular bullet has an all-lead core with a copper jacket that has the hole at the front tip.
    -An FMJ bullet is still lead, but has the hole in the copper jacket in the rear.
    -An armor-piercing bullet has a round piece of hard steel surrounded by a thin layer of lead, and then a FMJ jacket.
    ~
9

That was really bizarre. I didn’t see your post at all on preview. :confused:

10

Yep, DougC, that “regular bullet” you refer to is probably the type that is called a “HPBT” by some shooters. It stands for “HollowPoint BoatTail.” There are also bullets called “HPFB” which stands for “HollowPoint Flat Base” and probably other “HP” designs that I am not familiar with.

Earlier, I should have discussed the non-metallic tips found on some bullets. For most applications, the polycarbonate tip on modern ammunition is added to prevent tip deformation of the bullet while it is in a magazine. The “plastic” tip aids in guiding the round into the chamber when it leaves the magazine. I believe this “plastic” tip does little to nothing to aid in penetration, YMMV.

11

‘Armor Piercing’ means different things for different calibers.

9mm? You are pretty much SOL. Standard FMJ is about the best you will do. Some companies market a ‘conical’ round that supposedly is better at penetrating hard targets, but little testing and much hyping has been done.

5.7mm? Better. The round was designed with penetrating military-grade body armor in mind. Small round+psycho-high speed=Good effect against Kevlar and the like. Not so good against steel and such, but no so bad, either. Still just a FMJ round, though.

5.56mm? Now you’re talking. The NATO SS109 standard calls for a bullet construction (somewhat thicker jacket, somewhat 'pointy-er bullet, etc) that has good all-around AP capabilities. Not so good when hitting clothed flesh (as oppossed to ‘armored’, but you can’t have it all in a 5.56mm package. The M855, as the US forces call it, has better penetration than the M80 7.62mm round. Not bad for a dinky little round.

.50 BMG? You are in the small end of the big leagues now. The M20 round has it all: Armor peircing capabilites, courtesy of a hardened steel cap. Incendiary effect, courtesy of some magic pixie dust. (Probably something technical.) Also has a tracer effect. All in one little 750gr round!
‘Armor Piercing’ means very little outside of the Armed Forces, who have strict standards and test that a round must go through before it is called AP. And there are umpteen ways to achieve said level of armor piercing.

In the civilian world,‘Armor Piercing’ is generally thrown around as a scare tactic. (The infamous ‘teflon coated bullets’, as has already been pointed out.) Remember, so-called ‘Cop Killer’ rounds never actually killed a cop.

12
      • I have a bunch of old 5.56 I need to throw out anyway, so I ripped some open and took photos of what I had:

http://www.norcom2000.com/users/dcimper/bullet_types/bullets.html

(-Save this page if you want it, it won’t be there forever-)
~

13

It was very nice of you to do that, DougC. That gives a real good visual representation of what we are talking about.

14

A looong time ago, my brother and I shot at some silhouette targets with a 5.56. Standard M16/AR15 round. They where your basic copper jacketed rounds.

The targets where about ¼ inch thick plate steel. Not armor, just some steel. Used for .22 silhouette shooting.

Didn’t knock over any targets, the round went right through. Looked like it was melted more than anything .

Stock ¼ inch steel isn’t ‘armor’ but it would beat standing behind a bush.

I’m pretty sure just about any deer rifle would do the same thing. Doesn’t mean they are armor piercing though.

15
      • A regular 55gr .223 will go through maybe 5/8" of steel, a 30-06 will go through 1"… It’s hard to say how much will completely stop a bullet every time–at some thickness you only get a small hole and a bit of metal coming through, but if you’re butt was leaning against the other side of that metal, you’d be in major agony…
        ~
16

Depends on what you mean by “steel”. Steel has a tremendous range of resistance to puncture, depending on alloy, heat treatment, forming, etc. Anywhere from maybe 10,000 psi to 340,000+ psi.

I’ve never in my life seen a .223 pentrate anything like 0.5-inch steel of any kind. Maybe if you hit the same place two or three times. I’m not saying it’s incorrect, but I fear that I do find it difficult to believe based on my experience shooting a lot of things for tests. Can someone show me some cites of normal FMJ .223 going through 5/8" of even mild steel? :confused:

Also - are the standard Chinese/Russian military 7.62x39 steel-slug rounds “armour piercing” as it would be known, or is their composition/construction not intended for that purpose?

17

I don’t know if the 7.62x39 FMJ is INTENTIONALLY armor piercing. I did use an AK-47 on a “homegrown” backstop of 3/4" steel and you could see the rounds pushing through the steel.

18

Range on that was about 100 yards, by the way.

19
      • Yes, the cheap Chinese or Russian military 7.62x39mm ammo is steel-cored. It has a steel rod the length of most of the bullet with a truncated forward end. I didn’t have any on hand to cut one open–I had some cut-apart bullets somewhere, but I can’t find them so I had to cut more open for the pix on that webpage. You can buy bullets and ammo in that caliber made with plain lead bullets too though, so just saying the caliber of a gun isn’t really enough. If you buy the (US) Winchester or Federal ammo however, it isn’t-- the bullets are soft-points or hollow points.
  • As far as the .223 going through 5/8", like I said, sometimes some bit of metal will come through. Plain soft-point 55gr .223’s will sail right through .25 mild steel and often partly through .5" mild steel.
    ~
20

Everything you wanted to know about the 5.56x45, but were afraid to ask.

Anthracite, from the site:

I assume that ‘300 HB’ is some sort of hardness measurement. I dunno, they use a lot of big words at the site, and I just sorta look at the pictures… :wink: