Interlinked

Based on Swedish trials at least, acceleration performance of T-80U was not terribly impressive although it's certainly "enough" for it.

I think the obvious takeaway is that "simplicity" is not a correct way to describe Soviet tanks, not even by intent through doctrine. Intent was always to achieve best possible performance given the possibilities of the tank industry.

1K13 sight had independent vertical stabilization, used only when guiding missiles. The linkage to the gun had to be disengaged when used in the missile mode. Reloading was at least possible while the missile was in flight, and hitting targets at shorter ranges, certainly; there was no interlock that actually prevented firing when the tank was moving. IMHO the inability to fire on the move was only literally true if firing at, say, above 2 km, or if the target was moving.

That was not in the design requirements. Railway gauge dimensions were loosely restricted by the domestic gauge, not the International gauge, and even then it was more of a guideline than a hard requirement. It clashes with the general understanding that Soviets were going to invade Europe and planned everything around that idea, and that Soviet tanks were smaller because they were restricted by rail transport requirements, but there you go. Most beliefs about Soviet tank design are false - that is pretty much normal. This is a table of oversize categories for various tanks on the Russian railway gauge. As you can see, every Soviet tank was oversized! We might even conclude that it was actually the French who were secretly planning to invade the USSR and thus designed the AMX-30 to take advantage of the rail system. The T-72 skirt had a half-width of 1,795 mm, just barely within the H0200 category. The T-72 suspension half-width reached 1,685 mm, just barely crossing into the H2000 category. The tank was not vertically oversized, so its final oversize category was H2200. So it's marked with this code on the sides for rail transport.

The weight of heavy tanks was limited to 50 tons as a semi-arbitrary "line in the sand" to limit technical risk and mitigate the possibility of another monstrosity like IS-7. Medium tanks were limited to 36 tons (so that the's T-54's successor would have to weigh the same) as a semi-arbitrary goalpost to force the designers to reach the performance requirements by improving on a technical level instead of upsizing. Increasing the weight was tolerated if it could be justified - and it was, in the T-64A, T-72, T-80, and their follow-on variants, and their planned replacements. There was never any weight limit imposed by infrastructure. Dimensions were only slightly affected by the rail gauge, and the Soviets had a slight advantage because the Russian gauge was wider than the International gauge that most countries followed.

It seems appropriate to promote my book on the T-72 as an answer: T-72: The Definitive Guide to the Soviet Workhorse. To a large extent it depends on whether you are interested in the technology and engineering of making a good tank, or what a "good" tank is in the first place. From the technology side of things, Soviet tanks had many positive points, some bad points, and huge number of "interesting" points. Many of the "interesting" points come from the bad points overlapping with the positive points plus a healthy dose of uncertainty. One of those is ammunition capacity. For such a small tank the T-72A can hold up to 43 rounds of 125mm ammo, basically the same as a Leopard 2's 42 rounds of 120mm, but this was achieved by putting ammo everywhere it could fit. Ammo capacity was highlighted as a critical factor by the Israelis in the 1973 war and the smaller 40-ish round capacity of T-55s and T-62s was considered deficient compared to Centurions and Pattons. These all had no specially ordered or protected ammo stowage system. Soviet tanks all had ammo capacities hovering around 40 rounds because that's what the army wanted, and the number simply never changed even as guns went from 100mm to 115mm and then to 125mm and fire control systems became more sophisticated. Then in the 1980's you see the Germans and Americans settling on 40-ish rounds for their own 120mm gun tanks. Was 40-ish rounds too little, just right, or should it have been cut to a smaller number for safety's sake for the T-72?

The British Army has certainly has a long-standing interest to portray their tanks a certain way. The persistent myth-crafting about the Chieftain being designed to wipe out hordes of tanks from long range with impunity, promoting Challenger scoring the "longest tank kill in history", continuing to insist upon rifled guns being more accurate, etc.

I don't know enough about U.S. gun stabilizer development history to comment on the historical aspect, but in principle no, the recoil system layout issue is size rather than weight. The 75mm and 76mm guns were balanced as far as I know. If they weren't you could add a counterweight to the muzzle or to the back of the recoil guard as needed, no big deal.

Thanks

Hmm, the rim being an inconvenience is one thing, but I'm not sure, why the taper is a problem for magazines. Please elaborate.

What was the cause of unsatisfactory reliability in those magazines?

I stand corrected. Poor M47 doesn't get the recognition it deserves once again.

The whole topic was a victim of circumstance rather than legitimate design restrictions, IMHO. It's not that fitting a more powerful gun in the original Sherman turret was hard, but U.S. ordnance design conventions made powerful guns bigger than they should have been. U.S. tank guns followed a common artillery recoil system layout with the barrel between two recoil cylinders, the same as the M1916 field gun, just flipped sideways. That made the gun much wider across its recoil guards than it actually had to be, especially if you compared it to the 76.2mm and 85mm in the T-34, and the D-25 in the IS-2, where the recoil system was packaged in a sort of naval-style layout to not exceed the width of the breech. The 85mm in particular actually fits within the same dimensional constraints as the 76.2mm despite the huge increase in firepower. The compact M6 gun in the M24 showed that if they wanted it, the army could have 75mm firepower in a much smaller package with a concentric recoil system. But the next tank gun to have that feature was the M68 many years later. Also, the 76mm could have had a HE shell as potent as the 75mm one. If good fragmentation effect was incompatible with a high muzzle velocity with the steel of the time, the charge could just be reduced. The 75mm vs 76mm false dichotomy should have never existed if it weren't for circumstantial roadblocks.

I can see that nothing can be done.

By then, L60 was okay. Around the same level as the Leopard's engine in the 1960's, which should be considered respectable given the L60's congenital issues, but is otherwise uncompetitive internationally. I only assume that Centurion must have eventually caught up to a late war Sherman in reliability if its typical MDBF was at least triple of that Australian Centurion, not stating it for a fact. Considering that that Australian Centurion went through its original engine and one replacement, and its original gearbox plus two replacements, the failure interval was worse than Panthers when they were at their most dire. For a tank in the 1970's, late war Sherman reliability was not impressive. It was still not good in the '60s, or in the '50s, but it would at least be acceptable in 1945-1948 when the Centurion Mark 1 was first tested, but its reliability was even worse back then. EDIT: To top it off, during the Centurion's glorious service in the 1950's and 1960's as Britain's biggest tank export success since the Vickers 6-ton, it was widely regarded as a maintenance hog and burdensome to operate. One might even go so far as to argue that Leopard's subsequent success on the export market was because Centurion operators got tired of the upkeep and wanted something dependable for once.