Which Weapon?
If you are talking about the AR Platform, I just Function tested one of mine.
Using the Charging Handle, Lock the Bolt carrier Back with the Bolt Catch, Place the Selector on Safe.
Rounds are in Place in the Magazine, Bolt is Locked Open and Selector is on Safe.
It only requires a press on the Bolt Release to chamber a round and then move the Selector to Fire or Burst.
It about Two seconds to charge and fire the AR this way.
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That would be a dangerous condition to carry, with an AR bolt locked back over a loaded magazine. Well maybe not too dangerous if the safety is on, but any impact to the muzzle or the butt will likely cause the bolt to abruptly chamber a round, which at least will cause surprise and confusion. The bolt should be shut, all the way forward whether there is a round in the chamber or not.