Does the L55 truly have better penetration/performance than the L44? I was always under the impression that APFSDS had an “optimum velocity” somewhere around 1700m/s, so the benefits of having a longer gun were moot.
However, having just watched a video on the Israeli Merkava, the uploader claimed that the L55 had 10-15% improved penetration over the L44. Any truth to this? Should the Abrams switch over?
>the uploader claimed that the L55 had 10-15% improved penetration over the L44
You can discard the uploaders opinion due to use of video game style stats.
>”video game style stats”
Explain
Yes, the L55 performs better than the L44, but not in all cases, specially not for he Abrams. The DU rods used in the Abrams are already optimised for the L44 and the only difference would be better penetration at longer ranges, but not at closer ranges compared to the tungesten rods on the Leo 2 who profits from it in all cases, also the US L44 is a modified version and not all changes of the new L55 can be implemented in the Abrams, leading to more vibrations in the barrel and reducing the accuracy.
So a L55 would lead to the following things in an Abrams:
-little higher performance at longer ranges
-at the same time lower accuracy at longer ranges
-no advantages at close range, minimal worse accuracy
-no additional higher max penetration compared to the Leo2
You probaly can see now why the L55 hasnt been implemented in the Abrams.
Picture shows the theoretical penetration depth of different rod materials, real life numbers will be different.
>Israeli claims
Found your problem.
The uploader was trying to *critique* the Merkava, since it uses the L44, but okay.
>10-15% damage boost
>10MJ Constant Impact Energy
Doesn't this mean that the higher velocities are using a smaller penetrator?
Using the same penetrator, and gaining additional energy by higher velocity (as from firing the same ammunition through a longer barrel), you shouldn't see that drop-off of penetration at high velocities.
penetration in RHA is a standard for measuring anti-armor projectile performance. I don't see the issue.
>Does the L55 truly have better penetration/performance than the L44?
If you're firing tungsten ammunition, yes. The United States uses Staballoy.
>Should the Abrams switch over
No. Would require a lot of effort for zero benefit, the latest M829 is better than anything fired out of the L55.
>Does the L55 truly have better penetration/performance than the L44?
With tungsten rounds, yes. The increased velocity helps it get closer to the knee of the velocity/penetration curve..DU rounds reach their maximum penetration at lower velocities.
Easy way to think of it: Tungsten gets better with more velocity, DU gets worse. On the flip side, DU maintains its penetration potential at lower velocities better than tungsten (ex: the greater the distance to target, the slower the round is when it hits)
Which is irrelevant to making the inaccurate and over simplified statement that going from an L44 to an L55 gives you a 10-15% buff.
L55 would allow you to use a larger dart though
The L55 has considerably better performance (around 10-15%) With the new L55A high pressure gun having an additional 20%.
It is true that DU stops receiving a benefit after a certain velocity - but the drop is not much, and the bennifit of additional penetration at longer range outweighs it.
For example you may lose 5% penetration against a target 1km away, but you'll be gaining double digits at 3km+
Moving to the L55A, DU becomes obsolete unless you deliberately use a round with a lower charge for close ranges - which would be pointless.
No, it wouldn't. The breach is still the same.
So how is the weight of larger barrel balanced then?
As they found out in WWII with the 37mm, there comes a point where more velocity won't help and you have to have more mass behind the hit to penetrate. This is also why the US uses long rod penetrators instead of the shorter ones.
Aren't the Germans using the French L52 (including autoloader) for their slapped together hybrid tank?
Not by the breach
You can't use the same penetrator because the materials have different densities. This way all variables are constant, apart from one. The graph isn't really about velocity, it's about material. If someone wanted to test velocity, yeah, they'll do what you said.
No One Knows - Queens of the Stone Age
and the breach size would effect the size of the dart... how?
you do know what an apfsds is, right?
So what you’re telling me with these charts, tovarisch, is that tungsten darts fired from the L55 have superior penetration to the DU M829 from the L44?
So indeed, the L55 is superior with the right ammunition?
That's not what the chart says, at all.
its a retarded chart. L/D ratio of 30:1 and a 10mj constant impact energy?
it doesnt say anything other than give an idea of how the different projectile materials differ in terms of their theoretical curve...
Not necessarily. It's meant to show the difference in potential penetrative performance of different long rod material types by velocity. If you're using DU, you don't need as much velocity as tungsten for similar performance.
naturally, there's a lot more involved with the actual design, metallurgy, construction, etc with long rods that change things up, but this is just about materials. The main advantage of the L55 is that you can attain higher velocities without even needing new ammunition.
The thing with the L/44 and L/55 is that if you really want a leap in performance for velocity, you need to either bump up the size (ex 130mm), or you design a new cannon entirely with modern tech and metallurgy so you get a significant increase in acceptable chamber pressures. So compared to the two options, simply upgrading to L/55 is a viable upgrade if you're either not interested or capable of investing in complete gun and ammo upgrade. It's why the US made the XM360 as a sort of stopgap before needing to go all out with a complete gun system and caliber upgrade.
exactly. having a longer barrel doesn't mean that you suddenly can use a larger dart unless you're planning on making a dart 5m long
>you need to either bump up the size (ex 130mm)
That's what Nexter-KMW are doing with their new 130 mm gun.
Higher velocity is always superior and always gives superior lethality at range. Velocity drops off with distance, which is why penetration and lethality of APFSDS drop off with distance.
It does not often happen that tanks engage other tanks with their main guns at fifty feet.
Higher velocity also means flatter trajectory, less deflection by wind, and less correction needed for moving targets.
The only place where the L55 is not desirable over the L44 is weight. Modern MBTs are heavy beasts, right up to the edge of the capacity to transport them long distances. They already can't cross most bridges.
>Modern MBTs are heavy beasts, right up to the edge of the capacity to transport them long distances. They already can't cross most bridges.
And it's only going to get worse with the addition of active defense suites (both soft- and hard-kill) and drone launchers.
THE LENGTH OF THE DART IS LITERALLY THE MOST IMPORTANT FACTOR IN TERMS OF PENETRATION
>It's why the US made the XM360
The XM360 was made to get performance of the M256 into something that could be fired from a 30-ton chassis, while also having an electrically operated breech to fire the MRM rounds that were being developed at the time.
are you retarded?
nobody is saying otherwise. having a longer barrel does not mean that you're suddenly going to fit a dart in it that you couldn't fit in before. the l44 is like 5m long and the l55 is like 6m.
The XM360 also accepts higher chamber pressures than the M256.
Uhuh. And why are the projectiles the length they are at the moment?
so you are retarded
>The only place where the L55 is not desirable over the L44 is weight.
also barrell life, because of the increased pressure of the L55
no, you are fucking retarded
the breach dimensions have 0 (that is zero) bearing on the length of the projectile. With more muzzle energy however, you can make the projectile longer, especially due to being able to use a sturdier sabot
Isn't barrel erosion relatively unimportant in smoothbore guns?
>bullet size is totally dependant on the rifle barrel
>that's why m-16 bullets don't work in m4s!
this is you
you're a fucking retard
What are you talking about? I just told you, that using a sturdier sabot, which is something you can do with more muzzle energy, will allow you to make your penetrator either thinner or longer (or both), making a better apfsds round.
summer seems to have started early this year
I refuse to believe anyone is this fucking dumb. How do you fucking manage it?
your entire argument is that you can make a larger dart because the barrel is longer
that makes no fucking sense. think before you speak moron
no, because the muzzle energy is higher
is it difficult for you to understand text? Perhaps i can find more quora graphs for you?
>muzzle energy affects rod length
jesus christ you really are stupid
>More Muzzle energy means you can make the round "sturdier" which you couldn't do before
The fucking state of Jow Forums
>The only place where the L55 is not desirable over the L44 is weight.
and yanno, length. Longboi gonna have some additional trouble in built up terrain
The US already trialed the L/55 as the M256E1. It overloaded the stabilization system. There's also no real benefit for using DU over tungsten or vice versa, although tungsten performs slightly better against multilayered armor arrays than DU since the latter can't handle bending or other forms of deformation as well.
>lizard brain triggered by hearing percentiles
>video games are the only thing that measure in percent
>keeps quoting words OP didn't use
>inb4 irony
Man you're a special one.
you can use a sturdier sabot which means the penetrator can be longer, where a l/44 will be limited by its lower pressure
how are you able to operate a computer?
>where a l/44 will be limited by its lower pressure
The L44 and L55 have the same chamber pressure.
there's literally nothing preventing you from making a "sturdier sabot" with no difference in barrel length you mongoloid
Jesus thats sexy tho
Should just switch up to a redesigned turret and a 130mm in a few years instead.
>chamber pressure for two identical rounds fired in two identical chambers will be the same
wow, are you able to get a refund for that college degree?
You agree that the person user responded to was an idiot?
Let him have his memes
>*pissed of deer intensifies*
>the latest M829 is better than anything fired out of the L55
This is just not true. Not only does the L55 allow for longer penetrators, tungsten is on the same level as depleted uranium and may even be better.
>more velocity won't help you
Won't help, yes, but it doesn't actually reduce penetration unless you're also lightening the penetrator to keep energy constant.
>You can't use the same penetrator because the materials have different densities.
No, for the same material at different velocities.
>This way all variables are constant, apart from one
You can vary mass with velocity to keep energy constant.
Or you can vary energy with velocity to keep mass constant.
Both have the same numbers of variables held constant.
10MJ at v=2km/s means m=5kg
for a DU 30:1 penetrator, that means 2.23cm diameter x 66.9cm long.
10MJ at v=2.4km/s means m=3.47kg
For a DU 30:1 penetrator, that means 1.98cm diameter x 59.3cm long, no shit it penetrates 7 or 8% less.
See what I mean? I'm not saying the graph is wrong or "retarded" as another user said -- comparing on an equal energy basis is certainly more useful for some purposes than at equal mass, and contemplating different projectiles in the same gun (where the only way to get more velocity is to lighten the penetrator, keeping energy more-or-less constant) is more usual than the same projectile in different barrel lengths . But it's misleading in this particular application.
>Not only does the L55 allow for longer penetrators
Is the DM-63 significantly longer than the ammo developed for the earlier gun?
>tungsten is on the same level as depleted uranium and may even be better
We don't use pure DU, we use Staballoy.
Staballot is literally 99% DU
So how the fuck is that pic relevant to what OP posted?