# What makes a bullet armour piercing? **URL:** \ **Category:** Factual Questions\ **Created:** [November 28, 2005, 2:36pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051 "2005-11-28T14:36:06Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![DougC](https://avatars.discourse-cdn.com/v4/letter/d/7feea3/32.png) [@DougC](https://boards.straightdope.com/u/DougC)\ **Post date:** [November 28, 2005, 11:15pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/21 "2005-11-28T23:15:48Z")
- - - Armor-piercing ammo is different than regular ammo in that armor-piercing has a steel (or other harder-than-lead) core–tungsten is used in many larger cannon shells IIRC. - From my youthful shooting days I remember than with 223, 308 and 30-06 rifles, you really don’t see a whole lot of difference in actual results. A regular (lead-core) 223 bullet might go through 1/2" of mild steel, where a armor-piercing 223 might get through 5/8" or so. The holes do look a tiny bit different in their cratering, but with no direct experience you wouldn’t know the hole from one type from the other. …The armor-piercing ammo is really intended for use against _armor_, that being _hardened_ steel, and that isn’t common enough of a material for me to ever have shot at it much. Perhaps its action upon harder targets is more dramatic compared to lead, and maybe someone with military experience can comment. * * * - A US-civilian legal version of the FN P90 is set to go on sale early in 2006. Expected price is like $1400, way too much IMO. Originally FN only offered a full-auto and said that no US-civilian legal version would be offered, but I was told by a class-3 dealer that _very, very_ few US police depts expressed any interest at all in it, so we might guess that FN is not achieving the sales they had hoped for in the police and military markets. It is a nifty little piece but is after all only a blow-back carbine, firing a _pistol_-class caliber, only around 400 ft-lbs of energy. A .223 rifle for comparison has 1300 ft-lbs of energy; a .308 has up around 2300. And the ammo costs $1 per shot, and (using bottle-necked cases) is a bother to reload. ~ ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [November 28, 2005, 11:25pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/22 "2005-11-28T23:25:47Z")
> [@LiveOnAPlane](#): > > If fired at a target in the real world with nothing recording the event, it is highly unlikely. > > If fired at a target in the real world with Hollywood cameras rolling, it will happen every time. > > I think this has something to do with quantum physics, but can’t find a good cite. _shrug_ Works for me every time. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [November 28, 2005, 11:40pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/23 "2005-11-28T23:40:33Z")
Re: Putting the bullet in backwards - does that not cause an issue with: -the bullet is now unstable in flight -it might jam in the barrel causing…issues -it’s less aerodynamic and thus will hit the target with lower velocity and lower^2 energy? > [@](#): > > Nitpick: Only modified and Navy Garands use 7.62N (7.62x51mm). Most use .30-06. Isn’t that the same thing, except one is metric and the other is not? ---
**Author:** ![gossamer](https://avatars.discourse-cdn.com/v4/letter/g/f07891/32.png) [@gossamer](https://boards.straightdope.com/u/gossamer)\ **Post date:** [November 29, 2005, 12:03am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/24 "2005-11-29T00:03:15Z")
> [@msmith537](#): > > Re: Putting the bullet in backwards - does that not cause an issue with: > -the bullet is now unstable in flight > -it might jam in the barrel causing…issues > -it’s less aerodynamic and thus will hit the target with lower velocity and lower^2 energy? > > Isn’t that the same thing, except one is metric and the other is not? The 7.62 NATO is 7.62 x 51 mm. It’s commercially known as .308 Winchester. The metric designation of .30-'06 is 7.62 x 63 mm. ---
**Author:** ![Padeye](https://avatars.discourse-cdn.com/v4/letter/p/a9a28c/32.png) [@Padeye](https://boards.straightdope.com/u/Padeye)\ **Post date:** [November 29, 2005, 12:05am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/25 "2005-11-29T00:05:14Z")
> [@Stranger On A Train](#): > > If you want armor piercing, pull out Grandads old M1 Garand and get yerself a box full o’ surplus 7.62mm NATO. If you try going down to the local gunstore and asking for “a box of armor piercing bullets” they’ll laugh from here to Broadway. Aside from the caliber difference which has been mentioned there is one caliber of armor piercing ammunition that is legal to buy, surplus WWII vintage US 30 caliber, AKA 30-06. You can identify it by the black painted bullet tips. > [@msmith537](#): > > Isn’t that the same thing, except one is metric and the other is not? No, they are both nominally 30 caliber and use a 0.308" diameter bullet but the 7.62mm has a shorter body than the 30-06. The body taper and shape is the same so the navy was able to convert rifles by inserting a machined steel adapter in the chamber to make up the size difference. It’s not an ideal solution regarding accuracy since the bullet has to travel farther before it meets the rifling in the barrel but it works adequately. This caliber conversion is popular with target shooters but nearly all of them install a new barrel with a correct 7.62mm chamber and rifling twist better suited to the lighter bullet. ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [November 29, 2005, 12:13am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/26 "2005-11-29T00:13:16Z")
> [@msmith537](#): > > Isn’t that the same thing, except one is metric and the other is not? Nope. [The 7.62x51mm NATO](http://en.wikipedia.org/wiki/7.62x51_mm_NATO) (.308 Win) case is shorter than the [7.62x63mm Springfield](http://en.wikipedia.org/wiki/.30-06) (.30-06), permitting it to be more easily carried and loaded in box magazines used by modern battle and assault rifles. The actual ballistics of the standard issue rounds (M2 Ball) are quite similar, but the .30-06 has considerably more cartridge capacity and thus and be loaded higher in firearms built to accept higher pressures or heavier bullets, which makes it a more versatile all-around cartridge. Stranger ---
**Author:** ![Pushkin](https://avatars.discourse-cdn.com/v4/letter/p/ee59a6/32.png) [@Pushkin](https://boards.straightdope.com/u/Pushkin)\ **Post date:** [November 29, 2005, 10:13am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/27 "2005-11-29T10:13:46Z")
> [@DougC](#): > > A US-civilian legal version of the FN P90 is set to go on sale early in 2006. Expected price is like $1400, way too much IMO I was about to ask before I read your post. Seems like a cool looking gun to own, you can live out all your Goldeneye/Stargate fantasies to boot too 😛 ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [November 29, 2005, 10:25am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/28 "2005-11-29T10:25:56Z")
As a minor note, I was involved until a few weeks ago with a project to destroy the Canadian Forces’ supply of 7.62 FN-C1s. Those puppies woulda killed you deader than any Teflon-coated handgun round. Anyway, the Teflon is to protect the barrel from being gouged by the harder-than-usual slug. It’s not there to ease passage into the target. ---
**Author:** ![slaphead](https://avatars.discourse-cdn.com/v4/letter/s/e9bcb4/32.png) [@slaphead](https://boards.straightdope.com/u/slaphead)\ **Post date:** [November 29, 2005, 11:35am UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/29 "2005-11-29T11:35:40Z")
> [@matt](#): > > Again, this makes no sense to me since I would have thought the wax would make the arrow more likely to “skid off”, but those were the results reported. Somewhat different calibers and energies involved, but have a look at [this](http://www.navweaps.com/index_tech/tech-055.htm) for a discussion on how the nose material affects armour penetration in naval artillery. ---
**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\ **Post date:** [November 29, 2005, 12:35pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/30 "2005-11-29T12:35:39Z")
> [@slaphead](#): > > Somewhat different calibers and energies involved, but have a look at [this](http://www.navweaps.com/index_tech/tech-055.htm) for a discussion on how the nose material affects armour penetration in naval artillery. Interesting stuff! I do wonder if the same mechanisms apply to lower velocity projectiles - I don’t see shockwave effects or tip shattering being significant when an arrow strikes a helmet, for example. Nor is the geometry of a bead of solidified beeswax tightly controlled! I would love to see some decent pictures of these sorts of things actually hitting and penetrating. Flash-x-ray images could even show what happens as they pass through a plate. ---
**Author:** ![kinoons](https://avatars.discourse-cdn.com/v4/letter/k/a698b9/32.png) [@kinoons](https://boards.straightdope.com/u/kinoons)\ **Post date:** [November 29, 2005, 12:40pm UTC](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051/31 "2005-11-29T12:40:35Z")
as a lot of good factual data is already posted, i’ll just add my experiences and understanding. i have fired a p90 before. it looks awfully weird but it just falls into your arms and is one of the most comfortable weapons i’ve ever held. the 50 round mag is nice. but, ammo is damn expensive at .50 to $1.00 a shot. my understanding is the gun was built around the ss190 round which can beat body armor, but won’t overpenertrate. i also have an old tokerov my grandfather brought home from europe in wwii. i believe it shoots a 7.62x25 round and i’ve shot it through some old level 2 armor cleanly. [Previous page](https://boards.straightdope.com/t/what-makes-a-bullet-armour-piercing/333051.md?page=1)