My comments below are only correct if the action is made of three pieces of steel: blue, yellow and pink.

It looks blue and yellow will just transmit the rear thrust to pink. Pink will carry the rear thrust which will create an eccentric load in pink. The eccentric load create an outward bending moment in pink.

The bending moment creates two problems. First, the loads have a tendency to force the action open (split) and second, the bending moment causes a higher tensile load on the inside faces of pink.