i know a lot of fellas on the forum are ex-mil and have been away for a while..
so as we debate the merits of the 475 v 500, bigger popguns have been "percolating" elsewhere..
having gotten all the design mileage out of the 72/80/90 series platform, the "other guys" have decided to go "over hard" as it were with the t14 armata which currently totes the familiar 125mm (projectiles at a mile/second) with upgrade capability to the 152mm.
www.19fortyfive.com/2021/01/russias-t-14-armata-tank-is-a-modern-battlefield-warrior/all done ostensibly to defeat the abrams and german leo II..
which in the great overmatch game means upgrading our systems as well......
when the m1 was fielded, it came with the familiar 105mm which had been around a good long time - and was outmatched when it was delivered.
a few smarter guys got involved and the tip of our spear was upgraded to the rheinmetall 120mm. in use in the bundeswehr leo II.
so with the exception of "bang" power, for over 40 years since fielding, most considerations for the m1 have been fire control and survivability.
and as with most athletes, it has gotten heavier, current versions over 70 tons.
one day, even tom brady will notice his knees "ain't" what they used to be...
so in the great 475 v 500 debate, what matters most?
not exactly the same thing, but looking at the writing on the wall - the bundeswehr has started the leo III design process, more gun, more power, more survivability. the interim gun will be a "high pressure" version of the current 120mm, leading ultimately to a new 130mm main gun.
www.globalsecurity.org/military/world/europe/leopard3.htmand there isn't a whole lot of room left in the m1 turret to fit a new, bigger gun..
so how hard to you push your 475 or 500?
or do you surrender and go big frame - bfr and/or smith x frame?
Actually, Big Army realized that they were going to replace the 105mm gun on the M1 before it was ever fielded. The problem was that they wanted to field it NOW, as opposed to waiting until the turret was modified to accommodate the 120mm gun. So they went ahead and fielded an essentially obsolete gun with their new tank.
Also, the story goes that the GM-built version of the M1, with a conventional diesel engine, outperformed the Chrysler-designed version, and Big Army was all set to go with the GM design. And then Congress got into the middle of it. Chrysler was very nearly bankrupt at the time, and wanted the government to bail them out. The Army had been buying Dodge/Chrysler cars and trucks as non-tactical vehicles for a while by then (and probably still are). It was a seemingly logical step (using Washington logic) to insist that the Army buy Chrysler's tank. So they did. And Chrysler promptly sold off their Defense branch to General Dynamics. And the rest is history.
en.wikipedia.org/wiki/Rheinmetall_Rh-120