Nerd-fight! Ballistics testing on frangible ammo

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ADHDCanuck

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Thanks to an episode of NCIS.. I'm now geek-battling to discover fact from fiction in TV land....
Can anyone settle it? The guys at phoenix gun range settled the gangsta firing method myth for me... turns out what happens for real when you turn a semi-auto pistol sideways is hot brass ejects in your face and the slide rail takes a chunk out of your hand and your bullets go nowhere near where youre shooting.

Proposed TV Fact:
Frangible small calibre ammunition can not be tested for ballistics matching because it shatters too badly.

Thoughts:
- TV Relies on the magic of matching a bullet to a particular gun very heavily for plotlines. Is it really that simple/precise of a science?
- Frangible ammo still leaves a small portion (the base) of the round solid which would have striations on it would it not?
- Would it matter if it was small or larger calibre? I would think yes, but what do I know.
- This assumes the target is a human body (flesh and potentially bone impacts) or a wall, something environmental. not simply firing into a tub of jelly for science.

So WTF... is it stupid?
 
The Conclusion

Don't believe everything you see on TV
30-06_Bullet.JPG


Unless they are using something really exotic like a safety slug... odds are they'd be able to run ballistic tests on it.
 
I'm guessing it's true. Especially for high velocity small caliber frangible ammo like varmint grenades in a .17 fireball. Theoretically, if shot into an animal they pretty much end up in dozens of small mangled pieces scattered throughout the animal. Recovering all the pieces, then un-mangling them, and reconstruction the bullet to a level of quality for comparison with an equally f**led up test bullet shot from the same gun (ever think what the condition of the test bullet fired into the catch tank would look like?)... Pretty unlikely. We are talking Jeffersonian type skills here. Probably not gonna happen.

For anything slower than that though, I'd expect it to look the same as above
 
AHA! an opposing view, badass.

My concern lies with the base, as those photos show theres a solid base on that particular round that remains and might contain enough striations for comparison testing... the entire bullet not needing to be reconstructed.

Im wondering if the small ammo makes a difference since 17HMR is high velocity (2300 to 2600fps) the energy would be huge on a tiny round... and the base would be small...
 
A 20 grain Remington fireball is cruising at about 4000fps with basically the same bullet as an HMR. And they have a copper jacket where the base is pretty much the same thickness as the wall.

Google ".17 bullet cross section" under images. Now imagine the hydrological effect of that hitting tissue at 4000fps.
 
17cross.jpg


ok so even at 2500fps, that should really disappear on impact into a cloud of s**t.


seems the show might have had something... because they specified SMALL calibre. and large calibres have a solid base that remains.

I didnt realize the 17HMR base was the same thickness as the wall
 
Infact many, if not most rifle bullets have a jacket the same as the .17 with no thick base. It is a matter of velocity and mass. The less mass and higher the velocity, the less remains intact when the bullet hits hydrologic resistance. Other variables like tips and hollow points play a factor also, as that tiny plastic tip in the .17 v-max is literally designed to push through the bullet on impact, causing violent expansion of the bullet.
 
mikeystew said:
Infact many, if not most rifle bullets have a jacket the same as the .17 with no thick base. It is a matter of velocity and mass. The less mass and higher the velocity, the less remains intact when the bullet hits hydrologic resistance. Other variables like tips and hollow points play a factor also, as that tiny plastic tip in the .17 v-max is literally designed to push through the bullet on impact, causing violent expansion of the bullet.
Click to expand...

VERY good point.
I think it bears a little more discussion and authoritative fact finding to solve for good but I'd say the tv shows hypothesis is certainly probable...even likely.

Provided the calibre is small, and high velocity.
Certainly if the round ended up hitting something like a bone inside or a skull and then into more soft matter with room for expansion, there'd be almost nothing left of the round would there?

Time to call mythbusters. Gotta be something the Savages would be interested in.
 
The chance of a match is pretty slim, but it can happen. It is not an exact science, and actual ballistic techs probably wish it was as easy or as likely as shown on TV. It might work in tracking a gun from crime to crime, but determining ownership isn't as easy. Some states (and Washington, D.C.) keep ballistic records of new guns. Think about how useful those will be...:

Like most nutz, you probably fire 200+ rounds at the range...you think the first bullet will match the last bullet?

When you are done shooting you go home and clean your guns...this may also alter the bore, etc and change the ballistic "fingerprint".

If you are really keen, you may also need to replace a barrel, firing pin, etc. Ballistic records are pretty darn useless after that.
 
supernova said:
that isnt frangible ammo
Click to expand...

+1. Frangible ammo is designed to disintegrate upon striking a hard object.

http://www.globalsecurity.org/military/systems/munitions/frangible.htm

http://en.wikipedia.org/wiki/Frangibility


A frangible bullet is one that is designed to disintegrate into tiny particles upon impact to minimize their penetration for reasons of range safety, to limit environmental impact, or to limit the danger behind the intended target. Examples are the Glaser Safety Slug and the breaching round.
Frangible bullets will disintegrate upon contact with a surface harder than the bullet itself. Frangible bullets are often used by shooters engaging in close quarter combat training to avoid ricochets; targets are placed on steel backing plates that serve to completely fragment the bullet. Frangible bullets are typically made of non-toxic metals, and are frequently used on "green" ranges and outdoor ranges where lead abatement is a concern.
Click to expand...

If the show correctly used the term "frangible" (very unlikely, given the general lack of technical accuracy with anything related to TV/movies), then I would say that they are correct and it would be impossible to get rifling info from the bullet. In real life the only way to know would be to remove the projectile and see how many pieces it was in.


Mark
 
ditto a 17 or 20 grain vshock poly tipped?
given all these frangible ammo definitions, can it be reliably stated that 17HMR is a frangible round by design based on its size and composition? and can any other ammunitions be at least conversationally referred to as such with some accuracy?

given whats been stated above, it seems thats the purpose of the ammunition and its design, thin walls, poly tip, etc...
 
The bullet you tested looks to be a 62gr or heavier 224. That's hardly what I'd call Frangible. If you want to try a conventional bullet try something like a 36 or 40gr VMAX.

Then of course there are the true frangibles made out of a compressed copper powder. Those leave nothing but dust behind.
 
If driven fast enough and hitting a solid enough surface/material any bullet will fragmentate. That doesnt make it frangible ammo. 5.56 NATO will usually fragmentate in the human body inside 125 yds but past that fragmentation is less likely. It is not frangible. Nosler's Ballistic Tip Lead-Free varmint bullet is frangible h ttp://www.nosler.com/Bullets/Ballistic-Tip-Lead-Free.aspx watch the video on that page and check out the ballistic gelatin shots at the top of the page. It is designed to break up into tiny pieces and will not leave much behind that shows consistent engraving.
 
ADHDCanuck said:
ditto a 17 or 20 grain vshock poly tipped?
given all these frangible ammo definitions, can it be reliably stated that 17HMR is a frangible round by design based on its size and composition? and can any other ammunitions be at least conversationally referred to as such with some accuracy?

given whats been stated above, it seems thats the purpose of the ammunition and its design, thin walls, poly tip, etc...
Click to expand...

You can definitely consider 17 caliber V-Max ammo frangible... our experience with 17 HMR V-Max through a cardboard box is that it shreds apart... the casing is in multiple tiny pieces the poly tips separate... but... I have noticed striations on the small bits of casing... whether those bits could be reassembled and then compared to a known source... I highly doubt it... at least not with any kind of admissable certainty. And remember... we were shooting through two layers of cardboard... if the target is of a denser material (flesh & bone), I would expect the V-Max projectile to shred to a greater degree. The shredding that occurs would logically be less with HM2 since it shoots at a lower velocity... all else being equal.
 
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