What stops the AICS magazine from moving upward?

[NICKNICK]

If I recall, before the barreled action was installed in the AICS, the magazine was free to travel up through the magwell until the bottom plate on the magazine bottomed out on the chassis. With the receiver in place, the travel of the magazine is stopped. What part of the receiver is stopping the magazine?

Alternatively, where does the AICS magazine make contact with the receiver? Is it in the front, the rear, the feed lips?

Does having an AW cut receiver allow an AICS magazine to be pushed up higher into the action?

Thanks

 

[JohnnyK]

there is a mag catch that locks the magazine in place

 

[gme]

it contacts the action in the front

 

[Blackbrush]

When a cartridge resides in the mag, the cartridge under magazine spring pressure presses on the bottom of the bolt

 

[cal50]

Gravity.

(kidding)

 

[Boxcar]

The magazine is stopped by the bottom of the action.