This is not correct. An AR bolt MUST achieve full forward movement in order to begin its rotation - no rotation can occur until it is fully seated beyond the lugs of the barrel extension. An AR bolt does not begin rotation until it is past the barrel extension, it is impossible for it to rotate while still partially engaged in the barrel extension lugs. It IS possible that the bolt could not complete its rotation, however the bolt itself would be fully seated at-depth before any rotation has occurred. The firing pin cannot be exposed until the bolt is almost fully rotated closed, which means that even if you experience an early detonation in an AR, the bolt would have been so close to fully closed that it shouldn’t matter. If this was an “out of battery” (or… early?) detonation in an AR the bolt lugs would have been sheared.
Now, if a foreign object ignited the primer, you could have OOB detonation. Like if you manually dropped a loaded round into the chamber and then dropped the bolt to feed one from a magazine, you could punch the top of the bullet from the magazine into the already chambered bullets primer. That’s almost the only way to OOB an AR.
