So this is going to take a second, but bear with me. There's 2 facets that affect the 'rate of fire' for an M1: the way you calculate the firing times on the range, and where the ammo is stored in the tankReload times, and range shenanigansThere is a standard published in the tank crew gunnery skills test that you have to be able to reload the main gun in under 6 seconds, or we don't even let you on the range. (caveat: it was 6 seconds when last I was on an M1, which was over 10 years ago; it could've changed, but it's still going to be pretty low). So at a minimum, from the time the gun recoils, and ejects the aft-cap of the previous round, you have 6 seconds trigger the knee switch on the ammo door, pull out your next round, get it into the gun, hit the safety rod, and announce "UP!" that the round is ready to fire (and make sure you're out of the way of the upcoming recoil, too). There are guys that'll do it in 3 seconds, consistently.Now, that's a test in a stationary tank in a controlled environment. What about the range?There are gunnery engagements when you're on a scored tank range where you'll get 2 or 3 different targets to shoot, and your score depends on how quickly you knock them all down. Remember those 3-6 second reload times? They'll consistently hit targets 3-4 seconds apart. In fact, you'll have some crews hitting targets 1-2 seconds apart. Some of that is training, and some of it is gamesmanship.When you fire the main gun, you kick up a lot of dust. That dust will obscure the gunner's optical sights (tho not usually the thermals). When your sights are obscured, you call out "OBSCURATION" to let the tank commander know you can't see. This is very important in a battle b/c they're not necessarily using the same sights inside the tank (they can but often don't). The TC will help reorient the gun, and when the gunner finds the next target, called "IDENTIFIED" and the battle drill continues. The gamesmanship is this: when the gunner calls "OBSCURATION" the time between targets stops on the scorecard in the tower at the range. Once you identify the net target, the time starts again. A clever gunner will call "OBSCURATION" no matter what, while looking for the next target, so once it's identified and the time starts, the main gun is already reloaded and everyone's ready to shoot, and that's often 1-2 seconds between targets.So they are rarely so legitimately fast that they are actually hitting targets in under 2 seconds. But they're *required* to be fast enough to be reloaded in under 6 seconds, and after that it's up to the TC/gunner to find the target to shoot.Ammo storageOfficially, the M1A1-series holds 40 rounds of 120mm ammo. But that doesn't mean you have 40 rounds to shoot. There are 3 separate racks of ammo in the tank: 2 in the turret and one in the hull.The "ready" rack is right behind the loader, has a door with the knee switch, and is where he pulls ammo from during the engagement. Depending on your M1 model, there's either 17 or 18 rounds in here, but there's 2 of them in the top corner that are a son of an unholy bitch to get to.The "semi-ready" rack is behind the tank commander. These are in the turret, but not where the loader can access during a fight b/c there's a guy in the way. During a lull in the fight, you transfer ammo from the semi-ready rack to the ready rack for the loader to replenish. A good crew can move 8-10 rounds in under 5 minutes.The rest of the ammo is stored down in the hull, where you have to spin the turret to a certain angle, and point the gun a certain way so the breech isn't in your way, and pull those rounds out of the hull storage. It sucks as much as it sounds. Even an awesome crew takes at least 10 minutes to get those out and into the loader's ready rack.So all of that is to say that just b/c you hear that an Abrams "rate of fire" is ____ don't put too much stock into it. It depends on how you're calculating time between shots (are you breaking range ties for obscuration? counting target acquisition time?) It depends on how many rounds you're trying to fire before having to replenish the ready rack. And it (as always) depends on how good your crew is.
As noted in today's Tuesday Newsday!