A file on the front would raise your point of aim, depending how low it is shooting.
Try it off a good rest or sandbag, and see what the group looks like .
If it is new to you , let someone else shoot and see what they do, same thing, than you know it is the gun versa the gunny.
If it is way off, the rear could be built up with solder and iron, than flat black paint, or blue, but blue don't work on solder.