October 25, 2022: The U.S. Army has developed and is testing a new SEP (System Enhancement Package) update called SEP4 (or SEPV4) for its M-1 tanks. The last upgrade (Sep3) entered service in 2020 after years of testing. The new upgrade contains lots of incremental improvements of features the SEP3 tanks already have. This includes upgrades to the gunner’s sight and a meteorological sensor that collects data on weather conditions to improve accuracy of the main gun. The U.S. Army has led the world in tank gun accuracy for decades and the SEP4 features offer small improvements. Since the 1980s there have only been these incremental improvements for use against opponents who largely use T-72 upgrades that have not closed the wide effectiveness gap with the M1 and a few other similar tanks (Leopard 2, Chieftain, LeClerc and Merkava), A major advantage of the M1 is that it has more combat experience than any other tank, especially its primary opponent: improved T-72/90 models. The most recent combat experience for these tanks has been in Ukraine, when the most modern Russian tank failed in a spectacular fashion against modern Western portable anti-tank weapons. These infantry weapons have a long history of success and to capitalize on that Poland has obtained lots of them and even built its own versions.

Noting the similar success of the M1, a year ago Poland ordered 250 M1A2SEP3 tanks for $6 million each. These will be new tanks, not upgrades of older models. The M1A2SEP3 is also known as the M1A2C and is currently the most advanced version of the M1. The Poles consider this tank the best option to deal with any new Russian tank developments. The 66-ton M1A2C also includes the Israeli Trophy ADS (active defense system) which has proved itself in combat and is capable of defeating ATGMs (Anti-tank guided missiles) and RPGs (rocket propelled grenades). Deliveries will begin in late 2022 and be completed in about four years.

The 250 Polish M1A2s will complement the 240 used German Leopard 2A4s Poland obtained at bargain prices since 2002, along with a license to upgrade them to the 2A6 standard as the 62-ton Leopard 2PL. Poland is also upgrading over a hundred of its 380 older Russian T-72 tanks, most of them built in Poland during the Cold War and 225 PT-91s, a much-improved T-72 variant designed and built locally since 1995. Poland plans to retire its remaining T-72s as the M1A2s arrive.

Currently the most advanced Russian tank in service is the T-72B3, which is considered as good as the T-90, a 48-ton T-72 upgrade introduced in 1993 as the T-72BU but had a marketing name change to T-90. Over 3,200 were built and most were exported to India where they were produced under license. The 45-ton T-72B3 is cheaper and considered by Russian commanders and crews as equal to the more expensive T-90. Russia uses about 2,000 T-72B3s, put most of its 590 T-90s in storage and uses the T-72B3 for its active-duty units. Russia lost most of those T-72B3s in Ukraine since February along with many of the T-90s brought out of storage. Poland sees its M1 order as a prudent and successful investment.

Russia has a new tank design, theT-14, that improves on the T-72 but has not been in combat and is too expensive to purchase in large quantities. The 48-ton T-14 is a radical new design that appears quite impressive but has so far proved too complex and too expensive to mass produce. Mass production was supposed to have started in 2015 but technical problems and shrinking defense budgets halted that until 2020 when covid19 restrictions again delayed production until 2022. The war in Ukraine means further delays. Russia has fewer than a hundred development and pre-production T-14s which have been undergoing field tests with tank units since 2016. The T-14 has a three-man crew and a fully automated turret with the three crew all in an armored capsule under the turret.

The T-14 relies on a lot of new tech, some more advanced than any other Western tank has installed. Getting all that tech to work reliably has been a major problem. Getting all these problems fixed has made the T-14 more expensive, at about $4 million each. That’s twice what the reliable T-72B3 costs and Russian combat commanders and crews will have to be convinced that the T-14 works and is not just as reliable as the T-72B3, but also better at surviving in combat. Mass production to build less than two hundred more T-14s was supposed to begin in 2022. At the moment it looks like the Polish M1A2Cs will be the first American tanks to meet the T-14 in combat if Russia ever tries to make a move on Poland and has any new tanks to do it with.

The M1A2C tank is considered the best combat proven tank in the world. But there are many different models of M1s, which vary considerably in their combat capability. The earliest model is only about half as capable as the 2013 M1A2SEP2 model. The M1 is an old design with the first of 3,273 M1 tanks produced in 1978. This version had a 105mm gun. The first of 4,796 M1A1s (with a 120mm gun and depleted uranium armor) was produced in 1985. Another 221 were built for the U.S. Marines, 555 co-produced with Egypt and another 200 M1A1s sent to Egypt. Production of the M1A2 (with improved fire control systems) began in 1986, with 77 for the US Army, 315 for Saudi Arabia, and 218 for Kuwait. Another 600 M1s were upgraded to M1A2 standards. Deliveries of these upgrades began in 1998. In 2001 the army began to upgrade 240 M1A2 tanks as part of an ongoing SEP program with better thermal imaging and fire control equipment as well as communications and computer equipment that would allow tanks to operate a full color "battlefield internet" with each other, as well as headquarters and warplanes with similar equipment. By 2013 the army had upgraded 700 tanks to the M1A2SEP2 standard and built another 240 new M1A2SEP2 vehicles. The goal is to get at least 2,000 upgraded to M1A2SEP2 or higher in the 2020s.

So far over 10,000 American M1 tanks have been produced and most of them subsequently updated at least once, mainly in the 1990s. The army is planning to maintain and upgrade its M1 tank fleet (some 7,000 of them) into the 2030s. The M1 has already been in service since the 1980s and may become the first MBT (main battle tank) design to stay in service for half a century. Technically, some World War II tanks achieved that dubious goal but not in the service of a major power.

The SEP3 entered service in 2020 after being introduced for testing in 2017. SEP3 includes more improvements in the previous TUSK armor and RWS (remote weapons station) machine-gun upgrades as well improved electricity generation and distribution for all the electronic gadgets that need recharging (or whatever) as well as upgraded communications and networking and installation of VHMS (Vehicle Health Management System) and the use of LRMs (Line Replaceable Modules) to make it easier to upgrade or repair problems. The new communications features include ADL (Ammunition DataLink) to use airburst rounds. There is also an improved counter-IED (improvised explosive device) armor package, an upgraded FLIR (night vision heat sensor) and an APU (Auxiliary Power Unit) under armor to run electronics while stationary instead of the engine. The final addition was the Trophy ADS.

The SEP2/3 upgrades also expanded on MVP (Multifunction Vehicle Protection) features which includes external cameras that let the crew see what is going on outside at all times. (day or night or in bad weather).

The SEP program is continuous, upgrading existing M1A2 tanks to the new SEP3 standard as well as upgrading more M1A2SEPs to the SEP2 level. These upgrades keep the M1, or at least some of them, competitive with more recently designed and built tanks. The U.S. (mainly the army) has over a thousand of the SEP2 upgraded M1A2s and is getting as many of those upgraded to SEP3 as the budget allows.

The original M1A2SEP was developed in the late 1990s by upgrading protection and a few other minor fixes. These were followed after 2003 after combat experience in Iraq with TUSK (Tank Urban Survival Kit) and evolved into the SEP2 upgrade. TUSK was installed on hundreds of tanks headed for Iraq as well as several hundred more M1s that had battle damage repaired and TUSK upgrades installed at the same time.

TUSK entered service in 2007 with reactive armor panels for the side and rear of the tank, to provide added protection from RPGs. A slat armor panel protects the engine exhaust outlet of the tank from RPGs. A 1.5-ton belly armor kit, which can be installed in two hours, provides additional protection from mines and large bombs. Enhancements also include night vision for all crew members. There is also a telephone added to the side of the tank, so that infantry can more easily communicate with the crew when the tank is "buttoned up" (all hatches closed). The complete TUSK kit cost about $500,000 per vehicle and required about twelve hours to install all the components. Later additions to TUSK included a rear-view camera for the driver and RWS so the commanders' .50 caliber (12.7mm) machine-gun could be operated from inside the tank. This is particularly useful if the tank is taking a lot of small arms fire. This led to providing all-round vidcam views of what was going on outside the tank.

The M1A2SEP2 made most of the TUSK items standard and added more improvements like the RWS for the 12.7mm machine-gun as standard, as well in computer hardware, including color flat screen displays for the crew and software, including a new operating system along with improved TUSK ERA (explosive reactive armor), making the external phone standard and upgrading the transmission to make it more reliable.

The electronics on the M1 have undergone several upgrades so far, in addition to new ammo types for the main gun. A major enhancement was depleted uranium armor, which made the M1 virtually invulnerable from the front.

The one remaining item in need of major improvement is the 1,500-horsepower gas turbine engine. Past improvements here included electronic monitors on many engine components, an electronic logbook (to record all pertinent engine activity), and a maintenance program that makes the most of all this data. If the engine is monitored closely and constantly, it's possible to carry out maintenance in a timelier (before something fails) manner. The army would also like to develop an improved (more efficient and less expensive to maintain) engine, but that is also a costly item they can't afford at the moment.

MVP can also link to audio sensors that work with video sensors to automatically detect where enemy fire is coming from. The United States tested MVP on their M2 IFV (Infantry Fighting Vehicle). New anti-tank weapons are always being developed and the army wants to at least be able to afford new gear to deal with new threats. One threat that is currently ignored is top attack warheads (that put a shaped charge type attack against the thin top armor). There are also new types of mines and electronic threats. If the M1 is to survive for half a century it will have to evolve, as well as endure. The M1A2C is an evolutionary design compared to the T-14 which is a revolutionary design with a lot of new techs introduced at once.