Thread by @TotherChris

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings A few thoughts: Rambling alert - you have been warned.

Worth remembering that the the CT40 is a CT and not the conventional round that is often discussed when talking 90mm and 105mm.

CT40 actually means a 65mm case competing in the 50mm SuperShot category and not 40mm.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings With that in mind the first question, before we move onto calibre, is what is the purpose that the system will be used for? Anti-vehicle? Fire Support? Direct? Indirect? Distance? Effect?

The second, before we move onto calibre, is what platforms in what numbers and CONOPS?

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings Operation, purpose, volume and platform affect your choice.

The third question, before calibre, is what is available? CT40mm has entered production. 120mm turreted mortars with direct fire likewise. There are few 90mm and 105mm with the turret elevation and natures out there.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings That doesn't mean they don't exist or can't be developed, but by who, how long, what price? Who will produce, will the MOD (or your equivalent) accept from them? Local build? Export only? Under Core (or your equivalent)? Under Urgent Capability Requirement (or your equiv) only?

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings Calibre-wise, many have seen the 150mm at 1500m image for the APFSDS-T CT40... which is a clear penetration and not a "just" penetrated. Given the 30mm RARDEN is known to have defeated T-62 armour*.

*I know, I know

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings From an AP point of view, there's not much out there that a 90mm or 105mm suitable for indirect fire can penetrate that a CT40 can't. The threshold seems to have moved to the 120mm category. In that role, the former may be unnecessary, to a CT40 or similarly equipped arm then.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings GP wise, the CT40 and slightly larger calibres become a weight vs rate vs stored calculation in the fire support and "making holes in walls" point of view. This becomes a very difficult area. A 90mm/105mm will definitely make big holes...

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings ...CT40 can definitely make smaller holes and place an airburst through the same hole in the same volley to ensure the void beyond is clear. I'll leave this one to those more knowledgeable.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings Indirect fire wise. Assuming elevation (see CTI's turret brochure videos) the 105mm vs 120mm mortar debate is more about your need for direct fire support (hole punching) vs indirect fire support (suppression).

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings From a UK POV with the CT40 coming onstream (YMMV) I would argue numbers and system capability suggest the CT40 can handle the direct fire support role *sufficiently* for what conventional 90mm/105mm offerings can achieve. The UK at Btn level has two needs:

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings 1) Heavy indirect fire support in the 105mm / 120mm mortar category

2) Direct fire support in the 120mm category.

I'll tackle the latter first.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings Infantry need systems that can remove something they object to *immediately*. UK will have CT40 around, but there may be something bigger without a C2 to hand. If we're talking 90mm/105mm direct APFSDS fire, we need to talk 120mm with all the not-a-tank debate that accompanies.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings As for the former point (heavy indirect fire) this is again a nebulous topic. 105mm artillery or 120mm mortars? Range vs Weight? Or do we need move to 155mm artillery? Arguably so. Which is a Bde level issue. If so, the Btn still has the need and so 120mm mortar is a need.

@thinkdefence @pricejamm @nicholadrummond @Foliohat @Soerings So yes, back in 2012 TD was as prescient as ever, however as always the goalposts have moved with seemingly smaller systems able to cover most requirements, but with the upper reqs moving into heavier weight territories to counter them.

I'll leave you in peace for a bit.

/FIN