S&W 79G disassembly

I am taking apart my Smith & Wesson 79G CO2 pellet pistol to replace seals. I took off the grips. Now trying to separate the barrel/action assembly from the receiver, took out the screw in the back that holds them together and the back can swing up a little, but they still hold together in the front. I don't want to force and break anything. What's next to separate them?