Autoloader An autoloader or auto - loader is a mechanical aid or replacement for the personnel that load ordnance into crew - served weapon s , such as tank s and artillery . The term is generally only applied to larger weapons that would otherwise have a dedicated person or persons loading them . Semi - automatic firearm s are sometimes informally called " auto - loaders " . However , this is a derivation of the term " auto - loading " rather than a physical " autoloader " , as discussed here . An autoloader , as its name suggests , extracts a shell and propellant charge from the ammunition storage rack / compartment and loads it into a magazine , if the gun has one , or directly into the chamber of the gun if it does not . It can and often does replace a human loader . By automating the loading process , it can streamline and speed up the loading process , resulting in a more effective fighting machine . In addition , by removing the need for one ( or more ) crew member , the overall size of the vehicle can be reduced , which in turn reduces the amount of surface area that needs to be armored , and thus a vehicle designed to use an autoloader can benefit from a significant decrease in weight and size . Also , since an autoloader can take up less volume inside a tank than a human , it potentially allows for a lower profile , making the tank harder to hit . Autoloaders are mechanical devices , and therefore their reliability depends on how well they are made . History . Autoloaders were developed at the beginning of World War II . Their first combat use was in tank - buster aircraft such as the 75 mm calibre " Bordkanone " BK 7 , 5 cannon - equipped Henschel Hs 129 B - 3 . Autoloaders in the modern sense bear the closest similarity to those fitted to aircraft . Every Soviet - and Russian - derived tank since the T - 64 main battle tank has used an autoloader . Their use has been mostly shunned by American and British tanks , although the American T22 medium tank was one of the first to use an autoloader . Naval . In the modern era , autoloading is ubiquitous on any large ( 3 – inch , or 76 . 2 mm caliber or greater ) naval gun . The size of the shells , when combined with the more elaborate autoloading facilities available in the wider spaces of a ship , makes an autoloader much faster than human loaders . For example , the US 5 " / 38 Mark 12 can load about 20 rounds per minute . The Soviet / Russia n AK - 130 ( twin barrel 130 mm ) , using autoloading , can achieve up to 40 rounds per barrel per minute . The Italian 127 mm / 5 " Compact has similar performance . The largest caliber auto - loading naval rifles were the US 8 " / 55 Mark 16 , deployed on the three cruisers of the Des Moines class in the late 1940s , and the 8 " / 55 Mark 71 tested aboard the destroyer USS " Hull " in the late 1970s . Both weapons achieved a rate of fire of 12 rounds per barrel per minute , compared to 3 - 4 rounds per minute for the preceding hand - loaded weapons . The advent of jet aircraft , and the rate of fire required to engage them , hastened the adoption of automatic loaders on naval artillery . Development of the loading systems was often problematic , and reliability was seriously compromised in many cases . The US 5 " / 54 Mark 42 was derated from 40 rounds per minute to 34 to improve reliability . The Soviet / Russian AK - 130 was so badly delayed that the missile cruiser Kirov ( later " Admiral Ushakov " ) was forced to use two older weapons in its place . The US 3 " / 70 Mark 37 actually spent more time in design ( 13 years ) than in service ( 12 years ) due to severe unreliability . These problems are largely of the past ; the state of the art has advanced a great deal , and requirements have generally become less aggressive . Ground vehicles . Rate of fire . A modern autoloader for a 120 – 125 mm caliber weapon in good condition can achieve about 10 – 12 rounds per minute . This rating may or may not include the time required to bring the gun to the appropriate loading angle ( if required ) and then bringing it back up to firing angle after loading . This is fast , but not quite as fast as a human loader , for which claims of 15 rounds per minute ( at least for a short time ) are made . On the other hand , the very newest autoloaders claim to match this rate of fire . Furthermore , it is considered atypical to engage more than a few targets per minute in a tank . The autoloader may also have an advantage over rough terrain that may jar a human loader enough to disrupt his loading cycle . For weapons above 127 mm , the increased weight of the round pushes this issue decisively in favor of the autoloader . For 6 - inch self - propelled artillery , for example , autoloaders can typically achieve 8 – 12 rounds per minute , while humans typically achieve 4 rounds per minute . For sustained bombardments , this may not be so important for sustained firing rates for artillery is typically only 1 – 2 rounds per minute , but the rapid - fire capability is vital to shoot - and - scoot tactics to deliver enough fire and then avoid the rapid counterbattery response provided by modern counterbattery systems . On the other hand , even during sustained bombardment an autoloader could be useful , as the fatigue issues of loading an artillery piece for hours do not affect them . Survivability . The most common autoloaders store their ammunition in the turret basket , increasing the possibility of a catastrophic explosion should the armor around the hull or turret be penetrated . More armor protection , and isolation / separation of the ammunition from the crew compartment has traditionally been available in tanks with a human loader , which can decrease the possibility of cook - off , or protect the crew in case of an ammunition explosion . For example the M1 Abrams was designed to protect the crew from cook - off , and this is accomplished by storing the main gun ammunition in a compartment at the rear of the turret , which is separated from the crew by a rapidly power operated armored door , which is only opened for a couple of seconds each time the loader needs to grab another round , and the top of this compartment has special roof panels that are armored against outside attack , but are much less resistant to pressure from inside , so that if this compartment is penetrated by enemy fire , these panels will vent the explosion generated by the ammunition burning , while protecting the crew . Other western designs from the later cold war era to the present with manual loading have similar protective features . In contrast , the Soviet tanks of the Cold War which employ autoloaders store the ammunition on a carousel in the middle of the crew compartment , where any penetration by enemy fire is likely to incinerate the crew and blow the turret right off the top of the tank ( known as the jack - in - the - box effect ) . However , some newer autoloader designs also store the ammunition in an isolated compartment in the turret bustle , with blow off panels on top and the ramming mechanism underneath or in the middle . This allows for much better crew protection , but is disadvantaged because the loading mechanism located in the ammunition compartment reduces the available space and number of rounds that can be carried considerably compared to a similar sized compartment without machinery . With such a design , the loader crew member can be eliminated , but only half the ammunition can be carried ready , in the compartment with the autoloader . Therefore , such a tank usually stores additional ammo in compartmentalized storage at the bottom of the fighting compartment , like older manual loading tank designs . This storage can be surrounded by water , and compartmentalized to some extent , but the reduced crew must still transfer this ammunition to the autoloader at some point . However , such a design can also allow for the rapid replacement of the autoloader and reloading of the ready ammunition by making the compartment at the rear of the turret a modular component that can be easily replaced with appropriate support equipment , similar to how the US MLRS system is reloaded , but possibly even faster . Another possible advantage is that the door that separates the turret can only be large enough for one round of ammunition to slide through , rather than extending across the entire rear of the turret as in the case of the M1 Abrams - this could save additional mass and reduce the power necessary to operate the door , by using less massive armor for the same level of protection , since it would be part of the turret instead of a sliding component in a heavy frame . Size . Autoloaders are often implemented in an attempt to save on tank size . The T - 64 is an example of this . The current generation of tanks using autoloaders ( Russian T - 90 , Japanese Type 90 and Type 10 , Chinese Type 98 , French Leclerc ) all weigh between 45 – 55 tons . Tanks that do not use autoloaders tend to weigh in the 55 – 70 ton range ( American M1A2 Abrams , German Leopard 2 , British Challenger 2 ) . Fatigue reduction . The replacement of the loader and gunner crewmembers with a redundant commander and driver could allow crewmembers to rotate shifts . This would enable continuous operations on the battlefield .