Weapon effectiveness curiosities

[Other Means]

Well so the velocity is much more important but of course drag is proportional to velocity too: .

So a bullet that weighs half as much but is fired twice as fast will have 4 times greater Ek at the muzzle but the drag will slow it down to less Ek a lot faster.

[c3k]

Other Means,

, oh, yes, as a someone who actually has an Aeronautical Engineering degree, that drag equation is something that has dear memories to me. It seems simple at first, but then the diabolical professors always had an evil twist waiting...

Ballistics are fun: the flip side of looking at drag on a bullet is its Ballistics Coefficient. Or, how close does the bullet behave as if there were no drag? The BC of the .50 BMG is quite good. Boat tail, heavy, nice ogive, etc. all minimize the Cd in the above equation. Or, in shooter's parlance, increase BC.

I included the muzzle velocities, not to show Kinetic Energy at impact (since the velocities will change differently for each round), but rather to show how similar the muzzle velocities of the two weapon systems are, and to highlight that, indeed, the mass difference of the rounds is quite large.

So, using Force of Drag and F=ma, you get the deceleration, a, as a=F/m.

Hence, the mass of the round has an effect on the rate of deceleration, therefore it carries more velocity longer for a heavier round. The bigger bullet hits harder, longer.

Thanks,

Ken

[Other Means]

Sorry c3k, we cross posted. I was answering Steve - but looks like we were saying the same thing anyway

[akd]

Remember that kinetic energy is a big part terminal ballistics. And a big part, in fact a HUGE part, of kinetic energy is the mass of whatever is being chucked out of the barrel. Look at that picture of the .50cal vs. the .308 round. Even if the .50cal was traveling at a vastly slower velocity, the effect against whatever it hits (especially if soft) is likely to remain much greater. I've seen Afghan sniper vids of hitting Taliban at massive ranges (hundreds of meters, one at 1000m+) and the impact sent body parts flying many meters into the air and around.

Steve

Steve,

Please tell me you don't mean this video:

http://www.youtube.com/watch?v=h3zjA84vxW8

...cuz those are marmots.

[Battlefront.com]

Egad, the engineers are here to save the day. RUN!!!

Velocity absolutely has a lot to do with things. I didn't think to mention it because we were limiting the discussion to rounds which all have similar velocities (2400-3000 fps). In fact, the .50 cal round has slightly more velocity than the .308. Ouch. Not surprisingly the velocity of the NATO 5.56 round is higher than .308 or .50 cal.

AKD,

Are you sure about that? There's one that definitely looks Human. Where was the video debunked?

Steve

[SlapHappy]

Despite the insinuation that those are Taliban sniper victims, I also have had my doubts that was the case. Something about the video doesn't seem like a battlefield setting.

[Battlefront.com]

Yeah, that "not really a battlefield" thing struck me from the first time I saw this years ago. But like I said, one of them really looks like a person. In any case, my point about the target exploding is still valid even if it is a very large rodent :-)

Steve

[StrykerPSG]

Yeah, that "not really a battlefield" thing struck me from the first time I saw this years ago. But like I said, one of them really looks like a person. In any case, my point about the target exploding is still valid even if it is a very large rodent :-)

Steve

Steve, you're lossing it to have thought the yahoos in that video were actual Soldiers shooting taliban or people and that it would need debunking. Definitely a rodent and certainly hitting with a large bore weapon. Can tell you a .50 cal would certainly rip someone in half, they do not explode as seen on that video. Yet again, another dirtbag looking to claim heroics from the safety of his/her home. You could also guage the size of the target versus local vegetation, note the scrub around the video and scale it next to the flying pieces.

[akd]

AKD,

Are you sure about that? There's one that definitely looks Human. Where was the video debunked?

Steve

Steve,

Go here: http://www.rmvh.com/Scenes.htm

...and click on "Varmint Safari II previews: Rock chucks (3.2M)"

[Sgt Joch]

I read with great interest the articles AKD posted, both Falkner's "Wounding patterns of miltary rifle bullets" from 1989 and "small caliber lethality", thereby expanding my knowledge in an area in which I will admit I only had general knowledge, however I still have some questions:

-Falkner states that much of the wounding potential caused by the 5.56x45mm M855 comes from fragmentation leaving exit wounds up to 15 cm. However, I have seen other comments that the M855 does not fragment consistently and may travel 6-7" in soft tissue before it begins to yaw:

Though early M855 experiments showed the round fragments well in the lab, more recent testing has been showing inconsistent fragmentation. Partially because of the complex construction of the round, M855 has widely-variable yaw performance, often not yawing at all through 7-8" or even 10" of tissue. Testing has shown large batch-to-batch differences in yaw performance even from the same manufacturer, and given the number of plants manufacturing SS-109-type bullets, fragmentation performance is very difficult to predict. This is complicated by the low velocity implicit in using M855 out of the short barreled M4 platform.

http://ammo.ar15.com/ammo/project/term_m855yaw.html

2. the data appears conclusive that the 7.62x39mm M43 round exhibits little yaw and will generally produce through and through wounds. However Falkner states that the M67 round will begin to yaw in as little as 9cm leaving a 11 cm exit wound. It also appears that the Chinese manufactured 7.62x39mm rounds will begin to yaw as little as after 2-2.5" of travel in soft tissue.

So, unless I am missing something, the data does not appear to be that conclusive that the M855 has superior wounding capability to M67 and later rounds?

Secondly, which type of 7.62x39mm ammo is most likely to be in use by Syria and insurgents in Iraq and Afghanistan? Is the M43 still in use?

[Flanker15]

I'm pretty sure that video was showing off their "varmint grenade" bullets which have an violent fragmentation effect.

[Battlefront.com]

AKD,

Thanks!! You've filled in where SNOPES did not And might I say that I have nothing against hunting, but I do have some objections to people exploding a little critter just for a laugh. Call me crazy if you will, however I think I look pretty good by comparison next to someone who would willfully plunk down 20 bucks to watch small, cute, furry creatures explode.

Steve

[akd]

AKD,

Thanks!! You've filled in where SNOPES did not And might I say that I have nothing against hunting, but I do have some objections to people exploding a little critter just for a laugh. Call me crazy if you will, however I think I look pretty good by comparison next to someone who would willfully plunk down 20 bucks to watch small, cute, furry creatures explode.

Steve

Most people would. Pointless "sport."

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