why automatic rifles can’t use blowback reloading systems

Question

I’m not super familiar with firearms and usually only see them in video games. I notice that pistols and sub machine guns use something called blowback to load the next round from the magazine. My understanding is that the recoil of the round pushes the bolt back and ejects the bullet. This works for pistols and submachine guns like a Glock or MP40.

For rifles though, they have to be gas operated or put in a separate tube so that the gas can go backwards to push the bolt back. Why is this the case? Why can’t rifles like the M16 or AK47 simply use blowback and let the recoil of the gun push the bolt back and load the new round?

In: 26

Answer 1

They can be blowback too

FAMAS and G3 are blowback (with a mechanical delay mechanism)

There is nothing stopping this.

I don’t know enough about the subject to explain why the design choices are made, but blowback can be found on larger automatic firearms. Even cannons, too, like 30mm.