Why can't the shell defector on the AR be a rear sight?

[10-96]

Considering the age of this post, I can't believe nobody has really hit on the most important reason why a Shell Deflector cannot be integrated into a Sight. Mechanically, it would be possible. But what it really boils down to is this-- Your shell deflector would become a Sight Deflector and we all know that would summon bad juju. There. Ya'll can thank me later, I'll be here all night.

 

[Joe-ker]

Applause!

 

[Nanuk]

In 4 decades of using M-16, M-4 and AR in Military, LE and sport I have never had the occasion to need back up sights.

 

[DMK]

In 4 decades of using M-16, M-4 and AR in Military, LE and sport I have never had the occasion to need back up sights.

Consider yourself lucky.

I've never needed a seatbelt/airbag, or fire extinguisher, or 'needed' a gun.