For a start, the long gun barrel needed to drive an APFSDS round up to high muzzle velocities may be a distinct disadvantage in cramped surroundings.
Given that MBTs must still be able to counter the threat posed by enemy armoured vehicles, the traditional tank gun and APFSDS rounds seem assured of a long-term future, but today's limited budgets effectively rule out the development of tank variants optimised for urban warfare.
According to Rheinmetall, a 14 per cent increase in muzzle energy is registered on the L55 as compared to the L44 version when using APFSDS
Kinetic energy armour penetrators, such as APFSDS, simply create small holes that might prove fatal to armoured vehicles but which make little impression on buildings.
Rheinmetall DeTec has duly noted the changing scene and added its own HE-Frag round to the 120 mm smooth bore tank gun ammunition family, hitherto populated only by Heat and APFSDS.
The 40 mm GPR-T (General Purpose Round -Tracer) projectile is the partner to a CTA APFSDS, the GPR-T being ballistically less efficient than the latter by a long measure.
To this end considerable resources are being expended on improving the performance of both 105 and 120 mm APFSDS penetrators.
Typical of the latter is the array of non-DU 120 mm APFSDS rounds produced by GD-Ots in America.
APFSDS development continues with considerations being given to topics such as reducing sabot weight and initial drag, the in-flight stability of the penetrator rods and ways of reducing the incidence of rods bouncing off well-sloped target armour.
The gun can fire the current range of APFSDS
(armour-piercing, fin-stabilized discarding sabot), APDS (armour-piercing, discarding sabot), Heat (high explosive anti-tank) and Hef (high explosive fragmentation) ammunition (42 rounds carried below the turret ring) plus the 9M119M laser-guided missile (up to six of which may be carried) with a maximum range of 5000 metres.
Known as the C148, this employs a discarding sabot base and the training round launches a projectile matching that of the APFSDS
out to 2500 metres but then becomes unstable, so that the maximum range is reduced to some 7.
During the 1980s, a DU armour package was developed for the General Dynamics M1 Abrams tank that is supposed to be the equivalent of 1300 mm thickness armour against shaped warheads and 600 mm armour against APFSDS