USG New Medium Caliber Efforts - 30x113, 30x173, 50x225 & 40x53mm

Here are some slides from the recent Medium Caliber Industry Day. It was well attended by usual suspects. Very little international presence beyond Rhienmetall - fuze people or ammo people.

Future strategy changes:

  1. move away from Limited Competition with GD & ATK/NGC.
  2. More OTA efforts like DOTC
  3. More small business

Let me know if you have any specific questions.


MAST Technology Industry Day Summary.pdf (1.0 MB)

Thanks for posting it, Jay.

What’s OMFV (the Bradley replacement, I assume?). Interesting that for this vehicle the US Army appears to be leap-frogging over the 30 x 173 (and 40 x 180 S40 based on that) to a 50 mm based on a necked-out 35 x 228 round (so a modified Bushy III could fire it).

What keeps them from using the 50x330 RH503 cartridge which somehow became a Bushmaster too?

Rheinmetall had it going in the early 1990s. Then all got halted because no enemy was around. Then when SHTF on purpose they (Germany and half NATO) adopted 30x173 toy cartridges and next (when the new Russian MBT T14 and respective IFV generation will be fielded) we will have to buy back our own 50mm which as so often was 25 years ahread…
Well done Germany!

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Thyssen-Henschel+Bofors were experimenting with the 57 mm Bofors naval gun in a light tank/support vehicle in the 70s (Begleitpanzer 57). Could be interesting to see one of those slapped onto a Puma or CV90.


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The Russians did with their 57x348SR S-60 guns (nasty gun!). As they have plenty of surplus AA guns and ammo available maybe not the worst idea.
Just guess they need to design (or did already?) a new feeding system as clips are kinda complicated and limiting the value of the system.

They also developed a guided projectile for this gun and I would not be surprised (actually expect it) if there is als a new APDS or even APFSDS load.

I’m not up on the Russians as I wish I was. The Army wants Airburst ammo that will clear a initial row of buildings or trees or other and then go into airburst mode after. I dont remember which rounds this was the focus. Each round had different, but similar objectives.

Stepping back, its pretty awesome that all our technology is finally mature enough to pass USG muster. The future looks awesome to me…

I suspect that the Super 40 history has something to do with this (30 x 173 necked-out to 40 mm). When first developed, the APFSDS round had a very long case (218 mm, as I mentioned elsewhere) for a puller-type sabot, with a shorter (165 mm) case for the HE loading. This didn’t work too well, so the eventual length chosen was 180 mm, with the APFSDS having more of a mid-length sabot design.

The 50 x 330 was also designed for a puller sabot, with very little of the projectile exposed above the case. Maybe the US decided to adopt the mid-length sabot design they were familiar with, which meant a shorter case. Otherwise, the HE round would be mostly buried in the case with the rotating band high on the nose - possibly that would cause problems?

There is a firm in the Balkans offering turret mountings for surplus S60. Found my notes:

Valhalla Turrets of Slovenia, which in 2017 revealed that they had commenced a private-venture project to develop the Hildgard 57 Medium Remote Gun System (MRGS) using surplus S-60. It was intended for medium-weight armoured fighting vehicles (AFV) to provide increased firepower for ground fighting compared with the usual 25 to 40 mm cannon. A chain-driven mechanical ammunition handling system was planned, with 33 rounds of ready use ammunition (16/17 each of AP and HE). Both stabilised and non-stabilised models, with various optronics and fire control options, were proposed.

Also just spotted this: