BF2S Forums Gun politics, firearms ownership, and US 2nd amendment discussion

foot-pounds *shakes head*

Spark wrote:

foot-pounds *shakes head*

Engineering school was fun. Needless conversions when a professor decides to put everything in Imperial units and leaves in a metric factor in order to catch students not paying attention. Our textbooks were always in both units.

rdx-fx wrote:

Spark wrote:

foot-pounds *shakes head*

Heh.

Soopuer-sekrit US engineering trick:
Specs come in with US units, convert to metric to do the design work, convert back to US units for blueprints.
There is a special place in hell for the assclown that came up with "slugs" as an engineering unit of measure.

There is a kiddie pool in hell, filled with burning napalm, for freshly graduated US mechanical engineers who have no idea who Bernoulli, Reynolds, Young, or Hooke are too.
(I've had to train two of them.  Neither had a clue how to use AutoCAD, Excel, or Word. Neither had even heard of Matlab. Wasn't allowed to fire them - I quit after "training" the 2nd one.)

slugs and kips

rdx-fx wrote:

Dilbert_X wrote:

Depends what you mean by 'smaller'.

By weight of bullet, and diameter of bullet, 5.56x45 is smaller than most pistols.
55-77gr bullet, for 5.56x45, versus 115-230gr for 9mm to .45 ACP pistol.

By kinetic energy, it is closer to a pistol than a rifle
(5.56x45 62gr = 875 ft lbs, 9x19 115gr pistol 425 ft lbs, .45 ACP 230gr pistol 525 ft lbs)
as compared to my 7mm Rem Mag hunting rifle, at 180gr and 3616 ft lbs.
Even the relatively weak .308/7.62x51 is around 2500 ft lbs of energy.
.44 Magnum pistol (240gr @ 1400 fps) is over 1000 ft lbs

But still a good deal more energy than most pistols, assuming thats even a useful metric (see what I did there?)

According to a report I read the Mujahedeen feared the 5.45 Russian cartridge far more than the 7.62, as it released its energy in a way which caused far more serious wounds.

5.56 is not a pussy cartridge by any stretch.

Dilbert_X wrote:

According to a report I read the Mujahedeen feared the 5.45 Russian cartridge far more than the 7.62, as it released its energy in a way which caused far more serious wounds.

And the mujahadin had plenty of irrational beliefs and fears too.
Ballistics experts, to a man...

FatherTed wrote:

a .22 holds enough energy over a mile (generally) to still blow a hole the size of a grapefruit out of you on the exit wound.

no, it doesn't.

Dilbert_X wrote:

5.56 is not a pussy cartridge by any stretch.

it's good for ground squirrels and tin cans.

rdx-fx wrote:

There is a kiddie pool in hell, filled with burning napalm, for freshly graduated US mechanical engineers who have no idea who Bernoulli, Reynolds, Young, or Hooke are too.
(I've had to train two of them.  Neither had a clue how to use AutoCAD, Excel, or Word. Neither had even heard of Matlab. Wasn't allowed to fire them - I quit after "training" the 2nd one.)

There are some scary people to graduate from University in Engineering.
There are various types who really scare me:

The ones who never learned the subject thoroughly and scraped through the exams with a passing grade - but still think they're the greatest living expert on anything remotely connected with engineering even if they never even read about it let alone studied it.

The ones who did learn the stuff but think that because they learned it thats it, they don't have to ever apply it.
"Its OK, I'm an Engineer now, calculations are for students, whatever I dream up is guaranteed to work"

The ones who think what they learned at University is the end of all engineering knowledge, when its barely a smattering and a very simplistic one at that.

And of course the ones who embody all three attitudes......

Oh and the ones who you give a task and they come back after half an hour with "OK I give up, you can tell me the answer now".

/derail

Last edited by Dilbert_X (2012-07-28 22:35:13)

As I understand it the internal cavity causes sudden mushrooming and energy dumping

Comparing Russian Ammo - if 7.62x39 doesn't really do much damage until past 20-30cm, and most of it afterwards, while 5.45 does half of it before 20 cm, that might explain it.

So in similar circumstances a straight-through shot with a 7.62 would be an explosion with a 5.45 - assuming the average Mujahedeen isn't as fat as me or Jay.

Reciprocity wrote:

even with a muscle shot to a limb a bullet that goes ass over tits so quickly could cause a lot of icky damage.

Then there are bullets that spin apart at the cannelure, if they impact over 2500 fps..

Reciprocity wrote:

supposedly there is an air pocket in the tip of 5.45 7n6 that causes terminal instablility.  the bullet begins to tumble end over within a few centimeters of penetration.  hence the poison bullet moniker.

I think that may be the "stinger" ammo I'm thinking of.

If I recall correctly, that ammo was designed for the outer jacket to slow on impact, while the steel & lead core continued moving.
The core moving forward through the hollow air pocket caused the ogive (nose) of the bullet to open up, presenting a larger frontal surface area (i.e. enhanced mushrooming).
Fast opening jacket, with a large frontal area leads to rapid energy transfer to an unarmored target - or a "hammer and nail" impact on an armored target, with the jacket hammering the steel core through body armor as the jacket "splatters" on the surface of the body armor (putting the kevlar in the immediate area under tension, making it easier for the steel core to punch through).

So, a loosely bonded, rapidly expanding outer bullet jacket, combined with a lead & steel penetrating core, equals a round that is particularly nasty against both unarmored or armored targets.

It was probably fielded by the Soviets first to the Spetznaz and Airborne troops, using the (then new) AK-74.
So, if the Mujahadeen had a particular fear of those bullets, it was more due to the nastiness of the troops wielding them and the design of the bullet, and less to do with caliber of bullet.

rdx-fx wrote:

Reciprocity wrote:

supposedly there is an air pocket in the tip of 5.45 7n6 that causes terminal instablility.  the bullet begins to tumble end over within a few centimeters of penetration.  hence the poison bullet moniker.

I think that may be the "stinger" ammo I'm thinking of.

If I recall correctly, that ammo was designed for the outer jacket to slow on impact, while the steel & lead core continued moving.
The core moving forward through the hollow air pocket caused the ogive (nose) of the bullet to open up, presenting a larger frontal surface area (i.e. enhanced mushrooming).
Fast opening jacket, with a large frontal area leads to rapid energy transfer to an unarmored target - or a "hammer and nail" impact on an armored target, with the jacket hammering the steel core through body armor as the jacket "splatters" on the surface of the body armor (putting the kevlar in the immediate area under tension, making it easier for the steel core to punch through).

So, a loosely bonded, rapidly expanding outer bullet jacket, combined with a lead & steel penetrating core, equals a round that is particularly nasty against both unarmored or armored targets.

It was probably fielded by the Soviets first to the Spetznaz and Airborne troops, using the (then new) AK-74.
So, if the Mujahadeen had a particular fear of those bullets, it was more due to the nastiness of the troops wielding them and the design of the bullet, and less to do with caliber of bullet.

violates Geneva, no?

rdx-fx wrote:

Jay wrote:

violates Geneva, no?

Probably.

Soviet Union never really cared much for the Geneva Convention, AFAIK.

Hague, more likely. 

Hague Peace Conference of 1899 wrote:

The Contracting Parties agree to abstain from the use of bullets which expand or flatten easily in the human body, such as bullets with a hard envelope which does not entirely cover the core, or is pierced with incisions.

Shocking wrote:

An engineer that doesn't know excel? What the fuck?

I had one or two profs that were 'old school' that demanded pure hand calcs. They were useless profs, but the license exam is all written so it has its place I guess.