My 12 year old daughters 20ga Pardner pump compact is shooting about 7" or so low at 20yrds. Is there a way to fix this or will I need adjustable sights so I can adjust it out?

The gun has been sent back to Remington because of this issue and it had a bent barrel and they replaced the barrel and I got the gun back today and it is still hitting low not as bad as before but way to low.

I layed the barrel on a flat surface and it seems to be good and straight. Unlike before with one end off the straight surface.

I tried changing the aiming bead but it was just about the same height off the rib as the other bead.

I know this is a cheap gun but I didn't want to spend too much not knowing if she would like turkey hunting or not.