Watch as British tank shows off firepower in Germany

Don’t say that we’ll only get half a dozen😂

Tell them Jacko 🤗 🇬🇧

Enter Daniele, stage left…..

Re the gun- the answer is no. The accuracy of the smoothbore falls away over@2000m. For anti tank operation up to 2000m, this is offset by greater armour penetration thanks to the higher muzzle velocity and longer rod in the one piece ammunition. Some time ago I found ( can’t find it now ) an article detailing the capabilities of modern tank guns. The differences between the L20 and Rheinmetall did not seem enough to justify the change. So I assume commonality of ammunition was the deciding factor .

Okay at some point I might come back and talk about the Smoothbore, but: I’m going to pick apart your orbat a little bit.

First of all: British Regiments don’t work like that. Regiments are either administrative formations, not combat formations, in the case of Infantry, or Battalions in the case of Cavalry or Artillery. British Units are not combined arms, let alone Sub-units, instead they form battlegroups as needed. Generally speaking most British Army Infantry Regiments do not have all their Battalions in the same role in order to allow personnel to rotate between roles over their career and gain broader experience (Paras and Rangers are the exception and even then both have an asterisk)
Ares doesn’t carry six dismounts, it only carries four.

It don’t get why you’d want to build this around the Footguards, for starters you have a weird idea of having 15 Battalions (but four Challenger Regiments so, your 15 infantry Battalions don’t even divide evenly into four Brigades? These are also really massive AI Brigades if they have 4-5 Infantry Battalions, a Medium Cavalry Regiment and a Challenger Regiment), but anyway: You’d have to double the Footguards, and then add a few more battalions to keep the public duties battalions. (Lancers, Dragoons and Hussars also seems like a very arbitrary and nonsensical decision, especially when you consider that there are 4 Dragoon Regiments in the British Army atm (LD,RDG, QDG, RSDG) and none of them are on Challenger, but the Royal Tank Regiment currently is serving on Challenger). I’m also going to point out that your armoured infantry battlegroups(?) lack organic fires, recon, or anti-tank forces which currently come as standard in any British Infantry formation.

Let’s just unpack this wishlist:

1. Increase the Footguards from 6 to 17 Battalions (for reference the British Army has about 30 Battalions of Infantry)
2. Acquire and Ares Variant with 6 Dismounts
3. Acquire a Ajax variant with a 105mm gun
4. Cancel Boxer RCH155 and acquire a new tracked 155
5. New 50mm gun Ajax variant
6. Double the Challenger III buy.
7. Retain Boxer
8. Extra CS and CSS formations to be able to deploy the (presumably) 3-4 AI brigades you envision plus Boxer Brigades and RM.
9. Get the army to completely restructure how it functions at the unit level.

This is a REALLY expensive plan.

Technically for now, a rifled gun is more accurate than a smoothbore. As the spin helps maintain the projectile’s minute of angle (MOA) (accuracy) due to the gyroscopic spin. However, over distance the Earth’s spin affects this and the MOA starts to get wider. This is no different to long distance target shooting using a rifle..

Without the spin induced by the barrel’s rifling. A projectile fired from a smoothbore requires fins to maintain its stability through weather cocking. Which is where the drag of the fins causes the projectile to limit its weaving. The additional drag of the fins does means it is not as aerodynamically clean as a rifled projectile, so does shorten it range.

However, it is possible to make the fins active and control the projectile’s path. Which when married to a guidance kit, would make the actively steered projectile more accurate.

The primary reason why the Army wanted Challenger with a smoothbore gun is not due to reduced barrel wear or logistical commonality. But due to the armour piercing fin stabilised discarding sabot (APFSDS) dart being much longer than the CHARM dart used by Challenger 2’s L30 rifled gun.

As armour development has progressed and its effective thickness has drastically improved. You require a dart that has sufficient mass to overcome the properties of the armour. But also to have enough surplus length to push through the armour as the armour erodes the dart. Critically the dart’s velocity is major contributing factor on its armour penetration capability.

The Charm dart has reached the end of its development. The dart cannot be made any longer, due to the 2 part ammunition it uses. As the propellent bag requires a certain volume to allow the dart to reach its desired muzzle velocity. If the bag’s shape was changed to accommodate a longer dart, it would mean less propellent was available to push the dart down the barrel and therefore have a lower muzzle velocity.

Using the Rheinmetall Rh120 L55A1 gun with its one piece ammunition. The APFSDS dart sits encapsulated inside the cartridge by propellent. Therefore its length can be made much longer. Whilst still producing a very high muzzle velocity.

Sadly it does mean the tank can no longer use HESH. As HESH requires spinning to make sure it “splats” correctly on to a target. When Royal Ordinance were comparing their smoothbore prototype with the L30 prototype, they did create a HESH round using a spinning slipring. So it is possible to fire HESH from a smoothbore gun. However, due to the design of HESH it requires the fuze to be in the base. Which kind of precludes proximity fuzing or programmable fuzing. Which the smoothbore HE rounds now use to allow the rounds to be multi-use against a wider range of targets.