手动枪机步枪（Bolt action）是指需要以手动的方式完成子弹送入枪膛（上膛）与将使用过的弹壳退出枪膛（退膛）动作的步枪。由于每一次子弹上膛都是以手动的方式进行，这一类步枪只能进行单发射击，无法达到半自动或者是全自动射击的要求。

早期手动步枪一次只能装填一发子弹，射手将使用过的子弹退出枪机之后才能够装填下一发。这类称为单发步枪，也有双管单发步枪，因为其结构绝对地简单可靠，精度绝对地被保障了，但对于实战不便，现在通常只限于狩猎或射击运动，

稍后进入市场的步枪装配了能一次装填多发子弹的弹仓；射手只需要连续进行上弹与退弹动作就可以持续射击，直到弹仓内的子弹使用完毕为止。这也是目前手动步枪的主流型态。

Bolt action is a type of firearm action in which the weapon's bolt is operated manually by the opening and closing of the breech (barrel) with a small handle, most commonly placed on the right-hand side of the weapon (for right-handed users). As the handle is operated, the bolt is unlocked, the breech is opened, the spent cartridge case is withdrawn and ejected, the firing pin is cocked (this occurs either on opening or the closing of the bolt, depending on design), and finally a new round/cartridge (if available) is placed into the breech and the bolt closed. Bolt-action firearms are most often rifles, but there are some bolt-action shotguns and a few handguns as well. Examples of this system date as far back as the early 19th century, notably in the Dreyse needle gun. From the late 19th century, all the way through both World Wars, the bolt-action rifle was the standard infantry firearm for most of the world's militaries.