Ballistics Thread

We've already got a few discussions and there were threads about ballistics and round effectiveness but it'd be better to have 1 dedicated thread that'd clarify things or at least contain related shitflinging.

Attached: 400px-9mm_7,62mm_357sig_10mm_45SW_45GAP_50AE_002.jpg (400x300, 22.16K)

Other urls found in this thread:

en.wikipedia.org/wiki/9×25mm_Dillon
twitter.com/SFWRedditVideos

So, why are bottlenecked cartridges used so rarely in handguns despite many of the better performing ones being that way? 357 sig changes things a bit but what was the reason to not use them for so long? What do you guys think of .400 corbon?

And how viable are 10mm length cartridges in handguns for general purpose use? I've heard one issue with 10mm was that it was too big to fit into handle of comfortable size. If that's the case, can this issue be solved when using bottleneck cartridges like 9x25mm so that magazines are thinner in the front and allow better grip while keeping double stack? At what point do double feed magazines become impractical in handguns?

Because they are harder to design guns around and depending on the taper it can make conversions impossible.
A better performing round is less valuable to a military than a round that will allow for nearly double the cartridge capacity while being cheaper per unit to produce and increase the chances of an actual hit being made.
.45 died for a reason and it's because it's a bad handgun round for what you want a handgun to do in a military context; which is to provide suppressing fire for yourself so you can run away out of danger and let someone who doesn't have tens of thousands of dollars in officer training and command of a unit deal with the enemy.
This is why nobody uses pistols anymore, worthless in an actual military context.
Anything popular in the military will become popular in a civilian context because factories will be producing the ammo cheaper.
This is why 9mm is so popular when in a civilian defense situation where not spraying the area with 20 9mm rounds possibly killing (likely not) innocents would probably be a good idea, 9mm is cheap because it is produced more so people will use it over $1-$5 cartridges where you can barely get any training rounds in without taking away your beer money at the end of the week.
10mm would be useful to any organisation that is made up of mostly males who receive lots of firearms training but aren't supposed to use anything other than pistols.
Which is basically nothing in america at the moment.
Any situation that requires 10mm auto or S&W can easily be dealt with more effectively by using a carbine or a large capacity 9mm pistol which allows for more suppressing fire which is the actual important aspect of gun combat aside from actually hitting what you're aiming at.
Again for an organisation that employs mostly 6ft males that isn't a problem but again, that isn't a single instance of that except for the US marines who wouldn't use a pistol unless doing something sneaky beaky and in that situation they would use subsonic 9mm or .45 (realistically they wouldn't use a gun at all other than a backup)

The reason why i mention the military when you talk about civilian use is because the military rounds will be cheaper to buy, thus easier to train with, thus you will be more trained on them and more confident in a gunfight which is more valuable than having less training on a more powerful cartridge.
If you have little sword training it's probably better to pick up a dagger and not the massive broadsword that you don't know what to do with is what i'm trying to say.

9x25mm isn't bottlenecked, but I take you already know how it's basically a longer 9x19mm, expect that the evolution is completely different. I'd say it's an ideal cartridge because it's as long as a cartridge meant for a grip magazine could be, and it's diameter is also quite well established. So this is a "maximum" cartridge in size. In performance it's up there with .357 Magnum, and that should be good enough. You could also power it down to 9x19mm levels, or make a +P+ version that requires a weapon with a shoulder stock.

Attached: 9x19vs9x25mm.jpg (303x468, 94.01K)

Also, you could make the pistol work with 9x19mm or 7.62x25mm by just swapping the barrel.

Again in a civilian CC or OC situation the cheaper the round is the more training you can do and the most effective you can be with the gun compared to less training but a "better" cartridge.
All discussion of what the better round is is completely irrelevant if it can't be made cheap enough to be trainable on.
You could make the wonder-cartridge that fit every single perimeter for the "perfect general pistol round" and nobody would use it unless it was as cheap or cheaper than what most people use today.
Threads like these that don't mention defining aspects like cost and ability to train may as well be gun designer larp threads.

So its basically "the military can't bother with designing an effective round because it could be ok with a simple pea shooter and civilian market mostly follows the trend"?

Can you explain in more detail? Does bottlenecked design reduce the capacity of the cartridge? What are other disadvantages of the design if we compare a straight walled cartridge and its bottlenecked counterpart where their diameter, OAL and pressure are the same?


It's probably more economic to choose a widespread cartridge for actually doing work but it's not the topic of the thread, which is comparing cartridge designs and exploring what determine their effectiveness. If you shilled muh budget choice just buy more ammo into every discussion about ammo engineering we'd be stuck wit hit forever.


I was talking about 9x25mm dillon, not .38 super. It's a necked down to 9 10mm and it allows 2000fps with 90grain bullet.

...

This is from lib gen. I recommend you all take a look at what is on there, particularly the Russian has they have stuff written in Slavic moonrunes.

*as they have

I never said anything about 45, you stupid cunt. Why are 9mm shills sucj insufferable niggers?

Yeah, killing people. What a discovery.

Prove it, faggot. The only reason 9mm gayness is used is because military is stupid and cannot do a thing right and you know it, not some faggy "budget choice.

They could change rounds both when they dumped 45, swapped from revolvers for police and when they designed 10mm to turn it into a piece of shit like 9mm. they did the change anyway, it's that they are incompetent faggots, not that they don't have money.

Your brain is clearly lacking this important feature almost as much as 9mm does.

Tapered cartridges have less problems with feeding than straight walled ones and improve reliability, you insecure lying shill.

6.8 SPC has the same bottleneck as 556 does, you insufferable faggot. How about you stop pulling things out of your ass when defending your shitty decisions?

The outer diameter, you idiotic degenerate inbred mongoloid. 357sig has the same diameter of the case as 40SW or 10mm does.

Does britain only have brainlet engineers? Is this why you defend those incapable of good designs so eagerly?

No, you started sperging about how stupid it is to use anything but 9mm without actually answering the question.

Which is why you defend an utterly ineffective cartridge like a full retard.

9mm is so cheap BECAUSE it's adopted by military, not the other way round. If they adopted 10mm or 357sig they cost just as little, because ammo production is all about scale.

AK is popular and widespread because communists produced it like no tomorrow and shipped in anywhere armed people could cause trouble to their enemies. There are a lot more durable, cheap and effective designs, yet they were not so widespread so nobody bothered.

Where did you find a 5$ super round, cunt? At least try to contain your strawmanning so it isn't as clearly visible.

And it only takes more effort into designing a cartridge, which is often done by even civilians.

Attached: 6.8SPC.jpg (750x954, 441.7K)

Thanks, that's very interesting.

Is kinetic energy a good measure of round's effectiveness? If so, does it make sense to reduce the weight of the projectile in a round to gains velocity and therefore increase energy? At what point does this stop being the case? Is insufficient penetration the cause of this and how do you measure it, especially when using different expanding ammo?

What are you talking about? Bottlenecked cartridges are well-known to be more reliable than straightwall cartridges, on account of their headspacing on the shoulder rather than the case lip.

This was covered in the other thread, but you're thinking of energy the wrong way. You can't increase the total energy by decreasing mass because of conservation of energy; whether low mass or high mass, the projectile is being propelled by the same amount of powder, and the kinetic energy of the bullet will never be greater than the chemical energy stored in the powder.

I think you're assuming that there's a 1-to-1 tradeoff between mass and velocity, ie that halving the mass will double the velocity, and because energy has an (mv^2) term that implies energy would increase by 2, as velocity is squared. However, conservation of energy shows this is not the case; halving mass will only increase velocity by sqrt(2), and total energy stays the same.

Thanks, i did read that thread but by physics knowledge is a bit limited and is mostly in different language.

Ok, then why is there more energy in loads with lighter bullets?

Correction:
maybe i think of different "energy" but here's the data i'm looking at(i'm using the cartridge because there're less different brands compared) en.wikipedia.org/wiki/9×25mm_Dillon
Bullet mass/type Velocity Energy
90 gr (6 g) Gold Dot JHP 2,100 ft/s (640 m/s) 881 ft⋅lbf (1,194 J)
95 gr (6 g) FMJ 2,000 ft/s (610 m/s) 844 ft⋅lbf (1,144 J)
115 gr (7 g) Speer Gold Dot JHP 1,800 ft/s (550 m/s) 827 ft⋅lbf (1,121 J)
125 gr (8 g) FMJ-FP Match or Speer Gold Dot JHP 1,700 ft/s (520 m/s) 802 ft⋅lbf (1,087 J)
147 gr (10 g) FMJ-FP 1,495 ft/s (456 m/s) 730 ft⋅lbf (990 J)

Also, rate my autism. it was supposed to be a middle ground between 357sig and 9x25mm dillon because sig, while nice, does not copy 357 magnum and is similar to it only in a limited number of loads. By increasing case capacity of sig and making the neck longer we allow more powder and less pressure that (from my understanding) was the factor that limited its versatility to retain effectiveness. The neck also allows the usage of longer and more aerodynamic bullets that'd aid performance on longer ranges, especially from carbine barrels, as i've heard that 357sig does not preform in them as well as magnum does. The dillon itself is also unclear because it seems that is has a bit too much recoil, creates a lot of muzzle blast and is extremely loud and i'm unsure about how you fix that within the cartridge.

Attached: improved 357sig.png (889x880, 136.5K)

I can't answer that intelligently as I haven't looked deeply into the details of different 9mm loadings and how energy is transferred to them. However, assuming that all of your examples use an equivalent powder charge, you have to remember that in the real world, there are lots of things besides the projectile's mass and velocity that can determine final energy: the friction between the bullet and the barrel, the temperature and humidity that day, the elevation at which the shot was taken, drag function of the different bullets, and so on. When you take all the complicating variables into account, that can explain the differences in total energy.

Yeah, i also thought of that, maybe it's less effective to transfer energy into speed with heavier bullet as well. It's just no matter where i look it's that higher velocity loads carry more energy than heavy bullets based, aside from some loads from different manufacturers that just seem mild and don't compare to similar weight ones. Heavier bullet loads also recoil harder so maybe it's about that and conservation of energy?

Does anyone have any info on double stacked double feed pistol magazines? It seems really few modes had it, like Steyr GB, Five-seveN, Stechkin and one old H&K and 2 or so Russian pistols.

Attached: 74a28693517c6bf100b4ad7b51046c79b8a34ff4ad398fe7c910f59d23d2ed4b.jpg (215x255, 12.29K)

Completely untrue if you reload. 10mm is a reloaders cartridge.

Then specify it better, simply giving the nominal measurement of a cartridge can be rather confusing.
The measurements of that cartridge would be 9x23mm. Or 9x23mmSR to be a bit more precise. But even then you'd have to add its non-metric name to differentiate it from .38 ACP.

.38 Super technically is .38 ACP, like .45 Super technically is .45 ACP.

Yeah, sorry, my bad. I just forgot about that one and dimensions of x23.

Wait wait wait. .45 S&W? What?

It's .40, OP just has a typo.

Yeah, i downloaded it that way and never even noticed.