Tank primer #2 - Gunnery AKA The most fun you can have with your clothes on
We trained on this all the time. It was our primary mission. Placing steel on target. I'm sure it's pretty much the same now, but we shot a full crew gunnery qualification at least once a year, sometimes twice depending on where you were deployed. This consists of multiple engagements both stationary and moving against armor, both moving and stationary, and infantry. We also spent at least an hour a week in simulators fine tuning our crew interaction, fire commands, etc.
The M1 is so good at putting steel on target, you have to almost try to miss once you know what you are doing. We could hit targets out to 4000 meters, but most engagement was under 2000 meters. Training standards in my day were 6 seconds from target identification to target destruction while stationary and 8 seconds moving if I remember correctly, but most crews trained to a 4 or 6 second standard. By the early 90s we were no longer using daylight optics as our primary sights. Thermal was primary for all weather and light conditions because they were so effective. Vehicles GLOW in thermal sights in any weather, day or night, fog, smoke, hot, cold, desert, snow, forest, whatever. Troops are smaller but also stand out against background temp.
A typical firing engagement against enemy armor would begin with the Tank Commander (TC, duh) using his TC override handle to point the gun to the target he's evaluated as the most immediate threat. For example a stationary tank is considered a greater threat than a moving tank. Obviously a tank is a greater threat than a BMP or troops. He would then issue his fire command to the gunner "Gunner, Sabot, Tank" is an example. Usually the preferred ammo is already loaded at the beginning of the engagement, but this assumes the gun is empty. Loader then loads announced ammo or simply takes the main gun off safe and declares "Up". Simultaneously the gunner announces "Identified" to let the TC know he has the target and lays the main gun on the target. If the target is stationary, he then announces "lasing" and the range comes up simultaneously on his sight and the TCs panel. If the target is moving he "drops the lead" by quickly releasing the control yoke as the computer uses turret movement and range to calculate lead. TC quickly determines if it's a valid range (sometimes if there is intervening terrain you can get a bad lase) and if he determines it's good announces "Fire". After lasing the fire control computer will use the range plus a bunch of other factors like temp, humidity, gun barrel temp, ammo temp, elevation changes, and a myriad of others to adjust the reticle and the gunner simply replaces it center of mass and announces "On the way" and pulls the trigger.
Big boom follows, spent casing is ejected and breach stays open. On the 120 mm the casing is designed to burn up and all that comes back is the butt plate of casing with a longish metal rod so it's easy to get rid of. Loader then waits for next fire command to determine ammo needed and uses his knee to trigger a switch to open the ammo doors, pulls the required round, drops it butt down, rotates it over and rams into the breach which then closes. The above process repeats as needed. This doesn't cover machine gun engagements or other types of ammo or vehicles, but you get the idea.
CSB when I was in Korea as a PFC, I was the driver on the tank the won the Battalion cup for gunnery. Our gunner was an absolute wizard. On our first moving engagement the main gun hydraulic cylinder blew so the gun just dropped to it's lowest elevation. Turret still worked so as the gunner lined up, the TC just put his foot on the breach and pushed it all the way down and as it slowly came back down (it was very well balanced) our gunner would fire as it came down onto the target. We hit 4 targets like that on the move with no stabilization or computer range adjustment. He used the back up sight with a graduated reticle and used the TCs estimated range. Shortest target we hit was at 1100 meters and longest was around 1350 m. I doubt seriously I could have done that with any amount of practice.
TLDR, If the Ukrainian crews are as motivated as they seem, a brigade of NATO MBTs will absolutely roll through the Ruskies like crap through a goose, killing everything they see at ranges the Russians won't be able to comprehend.