I argued yesterday that the IFV concept of today isn't even close to the answer to a tactical problem that it was meant to be in its conception.
IFVs are compromise vehicles;
jack of all trades, master of none.
jack of all trades, master of none.

IFVs can support tanks with autocannon (20-40mm) and ATGMs (2-4km usually), but they're poorly supplied with ammunition for this .
They have elaborate fire control and weapon stabilization systems, but little capability against difficult aerial targets.
They can lay suppressive fire with a coaxial machine gun, but no better than tanks can do.
They are armoured for survivability, but much less than the main battle tanks.
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An especially disappointing compromise of the IFV is its passive protection. The armour protection is in between MBT and light, 'rear area' AFV armour levels.
Few modern IFVs attempt to come close to MBT protection levels at least against shaped charge and mine weapons; count me as unimpressed.
The whole concept of a high-cost compromise vehicle seems to deliver too little bang for the buck in general; especially too few infantrymen. The IFV concept suggests that IFVs are THE transport vehicle for infantrymen in heavy brigades. IFVs are expensive and relatively thirsty, so their quantity is dangerously low (A Puma-equipped Panzerbrigade with a single Panzergrenadierbataillon would end up with only about 300 infantrymen seats in IFVs).
There's no need to reinvent the wheel, though - we just need different compromises AND the readiness to get rid of an one-size-fits-it-all vehicle. Standardization benefits can be had with vehicle families of specialized vehicles just as well.
Few modern IFVs attempt to come close to MBT protection levels at least against shaped charge and mine weapons; count me as unimpressed.
The whole concept of a high-cost compromise vehicle seems to deliver too little bang for the buck in general; especially too few infantrymen. The IFV concept suggests that IFVs are THE transport vehicle for infantrymen in heavy brigades. IFVs are expensive and relatively thirsty, so their quantity is dangerously low (A Puma-equipped Panzerbrigade with a single Panzergrenadierbataillon would end up with only about 300 infantrymen seats in IFVs).

HAPC
The Israelis never bought into the IFV concept (and therefore deprived us of the opportunity to have it reality-checked in one of their wars). They kept the MBT/APC fleet until quite recently when they added a specialist vehicle concept; the heavy armoured personnel carrier (HAPC).

I think that makes a lot of sense; the relative lack of secondary fire/explosion threats in such a vehicle and the smaller silhouette (no turret) makes this concept even more survivable than MBTs (that doesn't need to be true for specific examples).
I propose to adopt this concept for the task of moving infantry on the battlefield till they dismount and do their job in the combined arms team of tanks, infantry and indirect support fires. HAPCs can carry a full group (10-13), not just the small ones we got used to see in IFVs (6-9).
The HAPC should be based on the same components and have the same (if not better) protection level as the MBT; the requirement for a rear door/ramp requires a different internal layout and therefore a different hull, though.
The HAPC concept has just one flaw; these vehicles are thirsty (heavy) and expensive.
Again, it cannot be the primary vehicle for a brigade's infantry. It can only fill the high survivability battle-taxi niche.
APC
The Heer had serious resource restrictions in WW2; one of these was a lack of SPW. It was only able to equip few Panzergrenadier units with SPW and equipped all else with trucks instead. That wasn't perfect, yet successful as the divisions had at least this reduced SPW inventory.
We're still in a similar situation, just at another level. We cannot afford (and sustain) HAPCs for all heavy brigade infantry. But we can afford to have some of the infantry in HAPCs and most in normal APCs (armoured personnel carriers).
Those APCs should have rear area protection standards; artillery fragment protection, bullet-proof, mine-protection and reduction of shaped charge behind-armour effects (spall liner).
Every such APC should be considered as a transport/utility vehicle, not as a combat vehicle. The self-defence armament could easily be limited to a 7.62 machine gun, at maximum a 20mm lightweight autocannon. The dismount strength should be the same as the HAPC's, but with a bit extra volume for extra equipment.
This is pretty much the classic APC concept as known by M113 and Fuchs. A cheap wheeled APC based on a medium truck chassis could satisfy as well.

RFCV
APC and HAPC replace the infantry transportation job of the IFVs . That's no complete substitution for an IFV, though.
The rapid fire capability of an IFV (coupled with usually much greater max. gun elevation in comparison to MBTs) is valuable and shouldn't be ditched.
A replacement vehicle for this (let's call it rapid fire combat vehicle, RFCV) should first fix a major flaw of the IFV; its inferior protection. A rapid fire vehicle with autocannon(s) would be a duel vehicle, in line-of-sight of the enemy just like MBTs. It needs MBT-level protection like HAPCs. This level of protection is not available for IFVs because the dismounts add too much volume and surface.
No matter how well an IFV is protected; a dedicated firepower vehicle that simply got rid of the dismount requirement (or limited it to a scout team's size like two) can be better-protected.
The RFCV should share the chassis with MBTs and have a IFV-like, but improved firepower.
It should be master with rapid fire, not just mediocre. Its ammunition should either leave no lethality wishes left or it should be available in such quantity that suppressive fire is possible for minutes (yes, I'm talking about heavier barrels than usual).
The Russians have shown off prototypes of such a concept, the BMP-T.
I'm still trying to understand the concept behind the automatic grenade launchers on that vehicle, but otherwise it's pretty much something that I could agree on.
My T-95 speculation could be understood as an upper limit, high-tech extreme of the RFCV concept. This upper end would be too expensive for a force that doesn't have huge quantities of medium tech MBTs in storage.
A variation of the RFCV concept could integrate a mortar for efficient indirect fire support; turreted medium mortars are proven tech and could easily be installed coaxial to an autocannon. The result would look a bit like the BMP-3 turret (a full gun is usually pointless for a vehicle that fights side-by-side with MBTs, though).
I have favoured a move away from the holy cow Schützenpanzerwagen / infantry fighting vehicle for years. The concept itself is outdated, was never fully realized in practice and it's in my opinion inferior to more specialized vehicles that actually delete the need for a medium chassis family. The IFV also hurts our heavy forces because it's a major reason for their terrible quantitative infantry weakness.
We're still in a similar situation, just at another level. We cannot afford (and sustain) HAPCs for all heavy brigade infantry. But we can afford to have some of the infantry in HAPCs and most in normal APCs (armoured personnel carriers).
Those APCs should have rear area protection standards; artillery fragment protection, bullet-proof, mine-protection and reduction of shaped charge behind-armour effects (spall liner).
Every such APC should be considered as a transport/utility vehicle, not as a combat vehicle. The self-defence armament could easily be limited to a 7.62 machine gun, at maximum a 20mm lightweight autocannon. The dismount strength should be the same as the HAPC's, but with a bit extra volume for extra equipment.
This is pretty much the classic APC concept as known by M113 and Fuchs. A cheap wheeled APC based on a medium truck chassis could satisfy as well.

RFCV
APC and HAPC replace the infantry transportation job of the IFVs . That's no complete substitution for an IFV, though.
The rapid fire capability of an IFV (coupled with usually much greater max. gun elevation in comparison to MBTs) is valuable and shouldn't be ditched.
A replacement vehicle for this (let's call it rapid fire combat vehicle, RFCV) should first fix a major flaw of the IFV; its inferior protection. A rapid fire vehicle with autocannon(s) would be a duel vehicle, in line-of-sight of the enemy just like MBTs. It needs MBT-level protection like HAPCs. This level of protection is not available for IFVs because the dismounts add too much volume and surface.
No matter how well an IFV is protected; a dedicated firepower vehicle that simply got rid of the dismount requirement (or limited it to a scout team's size like two) can be better-protected.
The RFCV should share the chassis with MBTs and have a IFV-like, but improved firepower.
It should be master with rapid fire, not just mediocre. Its ammunition should either leave no lethality wishes left or it should be available in such quantity that suppressive fire is possible for minutes (yes, I'm talking about heavier barrels than usual).
The Russians have shown off prototypes of such a concept, the BMP-T.

My T-95 speculation could be understood as an upper limit, high-tech extreme of the RFCV concept. This upper end would be too expensive for a force that doesn't have huge quantities of medium tech MBTs in storage.
A variation of the RFCV concept could integrate a mortar for efficient indirect fire support; turreted medium mortars are proven tech and could easily be installed coaxial to an autocannon. The result would look a bit like the BMP-3 turret (a full gun is usually pointless for a vehicle that fights side-by-side with MBTs, though).
I have favoured a move away from the holy cow Schützenpanzerwagen / infantry fighting vehicle for years. The concept itself is outdated, was never fully realized in practice and it's in my opinion inferior to more specialized vehicles that actually delete the need for a medium chassis family. The IFV also hurts our heavy forces because it's a major reason for their terrible quantitative infantry weakness.
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