Great gun. Your father-in-law must really appreciate you. To get better accuracy from the gun try a "rimfire" or airgun scope that has magnification from 4 - 14 or 4 - 16 maybe even a 6-18. But first find a brand and weight of cartridge that the gun likes. Most of mine have preferred CCI in 40 grain although the Winchester and Remingtons in 30, 32, 33, 36 grain have done well. The lighter the bullet the more "drift", left to right from the wind.
Best regards,
chalmitch
