OK, try this, shoot a lighter bullet, the bullet will exit the rising barrel sooner and therefore shoot lower
Are you shooting a 30-30? 32-40?
What weight bullet? 170? Then try a 150.
If not, What cartridge,

Can you post a picture of how the front sight is affixed?

One of the easiest options is to make a front sight out of a silver dime and then dress it down to the needed height.

Thanks
Mike