Do the poly M-14s have a goofy looking chamber??

[saskgunowner101]

Just picked up my Poly M-14s today and giving it a once over, it occurs to me this is the most bizarre chamber I've ever seen. For lack of better words....there are two cuts into the chamber at the rear . A little further out it has the same thing only bigger. This is normal??

 

[Canuck223]

You will note they correspond to the feed position(l,r) of the magazine. Normal

 

[saskgunowner101]

Thanks canuck.