'olBear' - The curved flat-spring ('R' on the schematic) puts considerable pressure on the hinge of the Magazine-Gate.

The tension on the spring can be reduced to a degree by removing the left Side-Plate. This relieves the tension of the follower-assembly.

A soaking of penetrant on visible areas of the Hinge-Bar and Magazine-Gate hinge will make disassembly easier.

Do not use excessive force. The Magazine-Gate needs to be held in position, while the Hinge-Bar is slightly rotated, 'back and forth', while at the same time pulling it forward out of the Gate.

(Caution - Do not use a 'punch' on the end of the Hinge-Bar to drive it out. This will deform it and cause problems).

I have a strong grip and can hold the Magazine-Gate in place, while withdrawing the Hinge-Bar. Sensible people use a padded "C" Clamp, to hold the Magazine-Gate in place on the receiver, while withdrawing the Hinge-Bar.