First of all, the size of the raw file never correlates to the size of the Photoshop file. If a flattened image is about 79MB, then we know that 79MB is the true size of each pixel layer in your file.
And if your stupid actions add more pixel layers, they're adding another 79MB each time.
Adjustment layers and masks add less size, but it still adds up. 511MB is very normal.
Just to check, are you working in 8-bit?