 Of the improvements , the slide lock is the one that really made the gun safer . This improved slide lock kept the gun locked until actual firing occurred which prevented the gun from jamming in the case of a misfire . The slide lock " stands in such a relation to the body of the firing pin as will prevent the firing pin reaching the primer until the pin has moved forward a sufficient distance to insure locking of the breech bolt . " This prevents the action sleeve " from being retracted by the hand of the gunner until after firing , and hence rendering the fire arm more safe " 
