Military Guns and Ammunition

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40x180   Ammunition 20-57mm

Started 29/11/20 by Refleks; 2700 views.
In reply toRe: msg 14

From: dskellogg


Well this one has me curious:

originally, the "Super Forty" did seem to settle on 40x180,

but in this recent Jane's article, regarding the latest Samson turret/RWS developments,

"The MK44S fires a complete family of 30x173 mm ammunition, including air bursting munition (ABM) rounds, and the weapon can be converted to fire 40x207 mm ammunition."

It's not like Jane's to make such a noticeable typo, so I'm very curious where the "Super Forty" development has evolved (at one point, mention was it was technically reduced slightly in diameter to 39mm...),

if indeed it is now closer to being standardized around 40x207 as opposed to the earlier 40x180mm... 40x207 is definitely not the  CTAI gun and its "chubbier" 40x255 cartridge.....


From: taschoene


dskellogg said:


I think you can see the evolution between this briefing, in 2010, where the case for the S40 is obviously only a bit longer than the one for 30mmx173...

...and this brochure c. 2012 where the projectile is highly telescoped and the case is almost the full length of the cartridge.  

  • Edited 30 December 2020 12:28  by  taschoene

From: dskellogg


Well that's interesting, and thank you.

Seems back in... 2015-ish? at AUSA they were pushing the XM813 (formerly MK44) being covertible from 30 to 40mm, but what was on display wasn't that mostly CTA-style ammo, but the earlier rounds in the first pic you have there.

Fast forward to 2 years ago, and now they're pushing the "Big Fifty" XM913 that can jump from the 30 to the 50mm, eyeing towards the Stryker Dragoon as a potential overmatch weapon vice the 30mm, and for the Bradley follow-on (can't wait for that future boondoggle).

Seems the Super Forty may have fallen out of favor..., compared to the overmatch the 50 will offer?

The unspoken word being, the 50mm EAPS course correction technology might be more readily adaptable to a slightly less volume Super 50 round, vs scaling down further to a 40mm.....


From: autogun


I believe that mistakes (possibly more than one) are being made in these sources. I have been following the development of the Super 40 for years, and have discussed it at length with the representatives of ATK and GD who are dealing with this. 

An extract from my Autocannon book (sorry the font is so small, I can't see a way to increase it):

Development of the Super 40 commenced under the ALACV (Advanced Light Combat Vehicle Armament) project initiated by the US Army's Armament Research, Development and Engineering Center (ARDEC), between 2000 and 2003. The objectives were to improve the performance of APFSDS projectiles by 30 per cent and to provide a much larger HE shell to increase the lethal area for air-burst by 400 per cent. The result of this programme was unusual in that the case length varied depending on the projectile. For the APFSDS-T round the projectile was mainly buried within the case, which was extended to 218 mm. For the much longer HEAB-T shell, the case was shortened to 165 mm. However, the different case lengths resulted in excessive barrel wear so further development resulted in a common case length of 180 mm. In all versions, the cartridge cases are straight, with no bottleneck, although in the latest 180 mm version the case taper has been increased to aid extraction, resulting in a slight calibre reduction to 39 mm (although it is still designated 40 mm). 

So the long-case APFSDS came before the 180 mm one. You will see that the brochure containing the long-case APFSDS illustration is dated 2012.

That still leaves the "40 x 207" which I have never heard of. I really don't know where that comes from, whether it is a mistake or ATK have been very busy since I left Jane's!  I wouldn't be too surprised by such an error, the journalists who write such articles are (mostly) not ammunition specialists and rarely consult those who are...

  • Edited 30 December 2020 15:32  by  autogun

From: DavidPawley


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.


From: renatohm


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


From: dskellogg


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.


From: autogun


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

From: renatohm


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.


From: poliorcetes


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