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Military Guns and Ammunition

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This is intended for people interested in the subject of military guns and their ammunition, with emphasis on automatic weapons.

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40x180   Ammunition 20-57mm

Started 29-Nov by Refleks; 2523 views.
DavidPawley

From: DavidPawley

30-Dec

dskellogg said:

XM913 that can jump from the 30 to the 50mm,

M813 isn’t just a Mk44 name change; it has dual linkless feed ammo boxes attached to the gun that elevate with it for reliability in feeding.
50 supershot is 35x228 necked up; XM913 is 35mm bushmaster III based with linkless feed and built for 50 supershot from the start.

The XM913 is mammoth compared with the M813.


https://www.overtdefense.com/2020/09/16/prototype-50mm-xm913-cannons-delivered-to-us-army/

renatohm

From: renatohm

30-Dec

Even in this case the Super 40 seems to be appreciably longer than the 30x173.

dskellogg

From: dskellogg

30-Dec

Nice, thanks for the comparison photo. 

I know I saw a similar lay out at an expo, just not at that one.

That display, they had the original 25x137 inline with the rest, including simulated weights for each. Comparing the 25 to the 50 was very... eye-opening, to say the least.

But it stresses the point I mentioned earlier: the middle weapon here being the M813, depicts the 30x173 to the left of its displayed ammo. That to the right, is the "old school" 40x180 seen many times many places, not the more encapsulated CTA configuration 40x207mm. That Jane's article was the first public mention I'd heard of it.

autogun

From: autogun

31-Dec

I suggest that you read my last post. 

The image below shows both of the "first generation" Super 40 rounds, the 40 x 165 HE and the 40 x 218 APFSDS. This dates from the 2000s.

As I said, this idea was dropped because the different case lengths caused barrel wear problems.

The common-case 40 x 180 was therefore developed, and the last I heard development was proceeding relatively slowly as there were no immediate prospects of any sales, the US Army having apparently decided to skip a couple of calibres and go straight to 50mm (whether they will get there is another matter, of course).

The ammunition shown in the above picture is shown in a cropped view below:

A "40 x 207" would involve a case length 34mm longer than the 30 x 173, and I don't believe the ones shown here are. I should emphasise that this is the latest picture of the Super 40 - the guns and ammo were on display at AUSA in 2019, so represent ATK's showcasing of their latest developments. 

I will endeavour to find out more, but as things stand I think that the most likely explanation is an error in the Jane's article.

  • Edited 31 December 2020 7:52  by  autogun
renatohm

From: renatohm

31-Dec

I did read your post.

The cropped area shows that the new kid is somewhat longer than the oldie - not significantly so, but at least one crimp length.

How long is that crimp? Some 10 mm? If so, then it's more likely a typo in Jane's.

If the crimp is some 30 mm long, then it wasn't a typo, and the design evolved since its last public appearance.

poliorcetes

From: poliorcetes

31-Dec

As time passes I find medium caliber AP more and more as a industrial solution searching for an actual military problem.

I mean, what is the probability of fighting between armed with such cannons? without MBT armed with 120mm guns?

How a super-uber-shot can be operationally justified if there are enough ATGM? I mean, ATGMs have more penetration capabilities, are guided, have greater range, some of them have NLOS capabilities, can be used dismounted in a less conspicuous way...

Indeed, I think that AHEAD/Air Burst ammunition is a more urgent need by far. a broad variety of drone / uavs are emerging as a very serious menace for armored vehicles, non-armored vehicles and dismounted infantry. Although 40mm HV grenade launcher with AB payloads are a stopgap solution, MAYBE 35mm or 40mm cannon with AB ammunition would offer enough advantages (speed and range) against drones in order to justify its adquisition. but I cannot see the actual need for armor-piercing, fin-stabilized, discarding-sabot 50mm ammunition

Farmplinker

From: Farmplinker

31-Dec

I think it's  case of better to have and not need, than need and not have.

Also, might this overwhelm APSs so ATGMs can do their job?

renatohm

From: renatohm

31-Dec

I do agree with you regarding AP.

An added bonus to increased AP performance, these necked out 40 / 50 also have much heavier HE shells, so I think that, in the end, it's all good anyway.

poliorcetes

From: poliorcetes

31-Dec

But I mean, against which probable adversary or target? I try to insert these concepts in the real world and in actual clashes. 

It's like sabretooth tigers. They have magnificent killing tools, but when megafauna mostly disappear, such sabres were useless. Or dreadnaught run: guns of increasingly more calibre and more and more armour. And suddenly, war ecosystem change and they were useless

What I try to illustrate are actual necessities or lack of them. Western armies need multiple layers of defensive resources against all kind of UAVs and their weapons. The threat is very, very real

Against which adversaries are going to be used such AP medium calibre guns and AP ammo? What is the probability of a clash in which a medium calibre gun is going to be enough decissive? Is there any fact-based reason for increasing calibres beyond "russian threat and their new 57mm turrets"?

DavidPawley

From: DavidPawley

31-Dec

renatohm said:

If the crimp is some 30 mm long, 

which it clearly is not.

Compare the difference in case length to the diameter of the 30mm projectiles: it’s significantly less.

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