Comments on: Provide room for a long ogive

By: Kirk

Kirk — Mon, 08 Apr 2019 02:28:31 +0000

I’m going to go out on a limb and wager that the folks who popularized the term for use describing computers, cell phones, and other technological toys likely did not have clue one about any previous usage of the term. It’s a bit of marketing-speak that I suspect was invented independently, and just happens to coincidentally match up with the technical physics terms as well.

I could be wrong, but I doubt it. There’s just not enough correlation between how the term is used in physics, and how the marketers used it. I’m also vaguely remembering someone having taken credit for coining the term back in the 1980s in one of the magazines like Byte or PC World…

It also kinda makes sense, when discussing things like motherboard size:

https://en.wikipedia.org/wiki/Form_factor_(design)

By: Isegoria

Isegoria — Sun, 07 Apr 2019 22:31:13 +0000

Apparently form factor is an old technical term that became popularized:

One of the first people to properly understand the transmission of light between surfaces was Lambert, in his book Photometria. In that volume (1760) he determined the fraction of light from one surface which was received by another surface, effectively a factor corresponding to the form (shape) of the surfaces. I reckon that some time after this the term "form factor" was used to describe this result, which would have been pretty famous. This became later corrupted by use in forestry, ballistics and high energy physics.

By: Anomaly UK

Anomaly UK — Sun, 07 Apr 2019 20:49:04 +0000

Is that the origin of the widely-used term “form factor”?

By: Alrenous

Alrenous — Sat, 06 Apr 2019 09:43:31 +0000

Wrong measure. You don’t want impact energy. We don’t all go around in chariots with 32 pound cannon on the front. If impact energy were stopping power, then perhaps we would. However, 99% of that energy will be wasted on a human target via overpenetration. Notably, sharp bullets overpenetrate more often. In short range combat you want hollow point bullets: autoflattening rounds.

At long range, of course you want the longest range possible, but also you can easily make do with single-shot rifles, since they can’t shoot back even if they find you.

I would prefer a graph of energy delivered to a ballistics gel target as a function of range, which will have a decidedly nonlinear character. If we add in the author’s helmet factor, then you’ll very quickly see there’s no ideal bullet. In medium range your choice will largely depend on your enemy’s favoured tactics.

In the (unlikely) event they prefer to pepper your forces from 2 klicks away, of course you can’t be satisfied with having to close 600 meters to return fire. If instead they’re usually ambushing you from 1 or less, then having 2 klicks of effective range is merely going to lead to flagrant overpenetration.

Unfortunately, I also suspect you’ll find that recoil and stopping power are rather closely related. Newton’s third law and all that. You can fire an aerogel filled round at high muzzle velocity if you like, but you’ll be lucky to put out an eye with those.

By: Bruce

Bruce — Sat, 06 Apr 2019 06:28:27 +0000

You know how howitzer rounds nowadays have just enough rocket thrust to cancel the vacuum behind the shell and prevent tumbling? With 3-D printing we could do that with long-range rifle bullets.

By: Phil B

Phil B — Sat, 06 Apr 2019 04:18:38 +0000

What do I want my projectile to do…? How does that support and integrate with everything else I’m doing in combat, and what trade-offs am I willing to accept?

That will never work. The British tried that approach and produced the .280 round for both the FN and their EM1/EM2 rifles but America insisted that a cartridge (which became the 7.62 x 51) was essential which duplicated the .30-06 ballistics. America also reneged on their agreement to adopt the FN FAL rifle as a trade off for having their round adopted as a NATO standard round and went for a modernised M1 Garand in the M14.

Seven years later, the M14 was abandoned and a round that became the 5.56 x 49 NATO, which oddly enough did NOT duplicate the .30-06 was adopted. Once again, this was unilaterally forced onto NATO as the standard round. The British 4.84 x 49 round was rejected out of hand by the Americans (no Goddam faggot Limey rounds here in the good old US of A) for no particular reason that I can find out, other than the “not invented here” attitude.

Now the Americans are toying with the idea of a 6.5 or the 6.8 Grendel which more or less replicates the ballistics of the British .280 round.

Welcome to where Britain was in the late 1940′s or early 1950′s …

https://armamentresearch.com/a-cartridge-in-brief-280-british/

http://armamentresearch.com/a-cartridge-in-brief-4-85-x-49-mm-british/

By: Kirk

Kirk — Sat, 06 Apr 2019 00:11:45 +0000

I think the fundamental thing that I’ve concluded about these questions we’ve been discussing over the last little while is that the process ought to start with first answering the question of “What do I want my projectile to do…? How does that support and integrate with everything else I’m doing in combat, and what trade-offs am I willing to accept?”.

From that, you design your projectile, then the cartridge case to support the projectile’s design and the ballistics you want from it, followed by designing the weapon itself.

This back-asswards crap we’re doing where the starting point is “Oh, we’ve got this 5.56X45mm case we’re trying to design around…”, or “Yeah, we want it to be a .30 caliber… For continuity…”? That’s just stupidity squared.

Start with deciding how you mean to fight, then follow that with your projectile’s ballistic solution, then case design, then weapon. Anything else is essentially half-ass, especially when you try to shoe-horn everything into a legacy design that has roots in the 19th Century.

What’s really needed, I’m afraid, is a clean-sheet design beginning with the tactics and operational intent of the military. You don’t issue a bullet-hose to troops whose ROE is going to be predicated on precision long-range fire that is going to have to be delivered onto carefully selected targets in among targets you don’t want hit. Likewise, if your tactics are based on mass movement and fire, you don’t issue those masses of troops a weapon that is designed to deliver precision fires in a deliberate manner.

Horses for courses–And, be damn sure you know what courses you’re meaning to run your horses on.