The angle isn't the only assembly problem with this 2 part model, the left forearm has a peg, which fits into the body. This peg is much too shallow to provide a strong bond so I had to file off the peg and replace it with a pin. There are two pre-drilled holes for pegs in this miniature. (I've inserted pins in them in these pictures so you can see their placement.) The right hand hole seems to be for a peg on the back of the right hand, but there is no such peg on my model.
I drilled the holes deeper and inserted pins in them so I could position the hands and gun without final gluing. My plan was to paint body and gun separately, but since I was changing the angle of the gun this turned out to be impossible. Because I've adjusted the angle more to my liking the pin in the right side of the body proved useless to me so I removed it and glued the right hand to the body.
Here is my progress so far.
I hope you guys find this helpful.